Organic electroluminescent element, material for said element, and light-emitting device, display device, and illumination device using said element

ABSTRACT

An organic electroluminescent element using a compound represented by the general formulae (I)-(IV), as disclosed herein, emits dark blue light and exhibits good chromaticity at a wide range of concentrations of light emitting materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage entry of International PatentApplication No. PCT/JP2012/069947, filed 6 Aug. 2012, which in turnclaims priority to, and the benefit of, Japanese Patent Application Nos.2011-179172, filed 18 Aug. 2011, and 2011-226618, filed 14 Oct. 2011,all of which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to an organic electroluminescent element.The present invention further relates to a material for an organicelectroluminescent element, or a light emitting device, a displaydevice, or an illumination device using the organic electroluminescentelement.

BACKGROUND ART

Since organic electroluminescent elements (which may hereinafter also bereferred to as “elements” or “organic EL elements”) are capable ofhigh-luminance light emitting using low voltage driving, they have beenactively researched and developed. The organic electroluminescentelements have an organic layer between a pair of electrodes, andutilize, for light emitting, energy of the exciton generated as a resultof recombination of the electron injected from a cathode and the holeinjected from an anode in the organic layer. Since the organicelectroluminescent elements can be provided as an element having diverselight emitting wavelengths, and have a high response speed and arerelatively thin and light-weight, it is expected that they can beemployed in a wide range of applications. Above all, it is important todevelop the development of an organic electroluminescent element havinghigh color purity and luminous efficiency is important in applicationswith full-color displays and the like, and the results of studies onvarious research and development have been reported.

PTL 1 describes that it is possible to attain light emission and alonger service life in the blue region in an element using a material inwhich a ring is formed with a single bond and a methylene chain withrespect to a fused ring structure such as pyrene as a fluorescentmaterial. In Examples of this literature, 3 kinds of compounds are usedas a blue dopant, which has a chromaticity of about (0.14 or 0.16) and amaximum efficiency of about 7.8 cd/A, described in Table 6.

Furthermore, the literature 2, which is well-known, describes that anelement having high efficiency and a wide gap (that is, considered toallow blue light emission to be performed) is obtained by using amolecule formed by subjecting benzofluorene to ring fusion and expansionas a light emitting material. In Examples of this literature, thespectrum of the element thus fabricated is disclosed, in which thewavelength is in a long and broad wave form and the maximum lightemitting wavelength was about 462 nm on average.

In addition, PTLs 3 and 4 disclose a material in which two indole ringsare fused symmetrically at 1-, 2-, 6-, and 7-positions of a pyrene ring,but according to the investigation of the present inventors, they havefound that there are problems, for example, that the materials have aninsufficient blue color purity and a change in the chromaticity due todeterioration by driving with a lowered luminous intensity (hereinafteralso referred to as a change in the driving chromaticity), and have anincrease in the voltage by driving (hereinafter also referred to as anincrease in the driving voltage).

CITATION LIST Patent Literature

PTL 1: WO2010/012328

PTL 2: JP-T-2006-512395

PTL 3: KR20110006915A

PTL 4: KR20110041726A

SUMMARY OF INVENTION Technical Problem

However, the present inventors have investigated, and as a result, theyhave found that the chromaticity of the organic electroluminescentelements described in PTLs 1 and 2 above may still be insufficient fordark blue colors in display applications or the like, and there is afurther need for achieving darker blue light emission. They have furtherfound that when these organic electroluminescent elements are driven fora long period of time, a change in the chromaticity occurs together withan increase in the driving voltage.

The present invention aims to solve the foregoing problems. That is, itis an object of the present invention to provide an organicelectroluminescent element emitting dark blue light and having smallchanges in the chromaticity and in the driving voltage even afterdriving for a long period of time.

Solution to Problem

Therefore, the present inventors have conducted extensive investigationsfor the purpose of providing an organic electroluminescent element whichemits dark blue light and exhibits good chromaticity at a wide range ofconcentrations of light emitting materials.

Here, PTL 1 mentions a position of a pyrene skeleton to which anon-aromatic ring is fused, and this literature describes that rings arepreferably fused in the major axis direction of the pyrene (1-, 2-, 3-,6-, 7-, and 8-positions), but does not specifically describe the reasonor the detailed mechanism thereof. On the other hand, PTL 2 does notdescribe a good position to which a pyrene skeleton is fused, as seenfrom the use of an exemplary compound having a structure havingnon-aromatic rings fused so as to connect the major axis direction andthe minor axis direction (4-, 5-, 9-, and 10-positions) of two moleculesof pyrene in [0119].

Therefore, at that time, it could not be expected from the knowledge inthe related art if a material for an organic electroluminescent elementemitting dark blue light and having a small change in the chromaticitywith respect to the concentration of the light emitting material can beobtained by changing the structure of a pyrene-based compound.

In this regard, the present inventors have found that by using apyrene-based compound in a specific structure having a ring fused in aspecific direction as a light emitting dopant for an element, an organicelectroluminescent element emitting dark blue light and can be obtained,which could not have been achieved in the related art. They have furtherfound that the skeleton of such a compound having the structure itselfemits short-wavelength light and it is not necessary to shorten thewavelength by additionally introducing a substituent having a specificstructure into the skeleton as in the fluorescent light emittingmaterials known in the related art.

That is, the present inventors have found that by using a pyrenederivative having a specific structure, the aforementioned problems canbe solved, thereby completing the present invention as described below.

[1] An organic electroluminescent element having:

a substrate,

a pair of electrodes including an anode and a cathode, disposed on thesubstrate, and

at least one organic layer including a light emitting layer, disposedbetween the electrodes,

in which at least one kind of compound represented by any one of thefollowing general formulae (I) to (IV) is contained in any layer of theat least one organic layer.

[In the general formulae (I) to (IV), R¹ to R³⁷ each independentlyrepresent a hydrogen atom or a substituent, but two adjacent groups outof R¹ to R³⁷ are not bonded to each other to form a ring. X¹ to X³² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵ each independentlyrepresent a hydrogen atom or a substituent. A¹ to A³⁸ each independentlyrepresent CR⁶⁶ or N. R⁶⁶ represents a hydrogen atom or a substituent,and when two adjacent groups out of A¹ to A³⁸ are CR⁶⁶, the two R⁶⁶'smay be bonded to each other to form a ring structure.]

[2] The organic electroluminescent element as described in [1], in whichat least one kind of compound represented by the general formula (I) or(II) is contained in any layer of the at least one organic layer.

[3] The organic electroluminescent element as described in [1] or [2],in which at least one kind of compound represented by the generalformula (II) is contained in any layer of the at least one organiclayer.

[4] The organic electroluminescent element as described in [3], in whichthe compound represented by the general formula (II) is a compoundrepresented by the following general formula (V).

[In the general formula (V), R⁴¹ to R⁴⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁴¹ toR⁴⁷ are not bonded to each other to form a ring. R⁴⁸ to R⁵⁵ eachindependently represent a hydrogen atom or a substituent, and twoadjacent groups out of R⁴⁸ to R⁵⁵ may be bonded to each other to form aring. X⁴¹ and X⁴² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵each independently represent a hydrogen atom or a substituent.]

[5] The organic electroluminescent element as described in [4], in whichin the general formula (V), X⁵¹ and X⁵² each independently represent alinking group represented by any one of CR⁶¹R⁶², NR⁶³, and O.

[6] The organic electroluminescent element as described in [4] or [5],in which in the general formula (V), X⁵¹ and X⁵² are each independentlyrepresented by any one of CR⁶¹R⁶², NR⁶³, and O, and X⁵¹ and X⁵²represent different linking groups.

[7] The organic electroluminescent element as described in any one of[4] to [6], in which in the general formula (V), at least one of R⁴¹ toR⁵⁵ and R⁶¹ to R⁶⁵ is a substituent having any of a fluorine atom, analkyl group, a silyl group, and an amino group.

[8] The organic electroluminescent element as described in [1] or [2],in which at least one kind of compound represented by the generalformula (I) is contained in any layer of the at least one organic layer.

[9] The organic electroluminescent element as described in [8], in whichthe compound represented by the general formula (I) is represented bythe following general formula (VI).

[In the general formula (VI), R⁷¹ to R⁷⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁷¹ toR⁷⁷ are not bonded to each other to form a ring. R⁷⁸ to R⁸⁵ eachindependently represent a hydrogen atom or a substituent, and twoadjacent groups out of R⁷⁸ to R⁸⁵ may be bonded to each other to form aring. X⁵¹ and X⁵² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵each independently represent a hydrogen atom or a substituent.]

[10] The organic electroluminescent element as described in [9], inwhich in the general formula (VI), X⁶¹ and X⁶² each independentlyrepresent a linking group represented by any one of CR⁶¹R⁶², NR⁶³, andO.

[11] The organic electroluminescent element as described in [9] or [10],in which in the general formula (VI), X⁶¹ and X⁶² are each independentlyrepresented by any one of CR⁶¹R⁶², NR⁶³, and O, and X⁶¹ and X⁶²represent different linking groups.

[12] The organic electroluminescent element as described in any one of[9] to [11], in which in the general formula (VI), at least one of R⁷¹to R⁸⁵ and R⁶¹ to R⁶⁵ is a substituent having any of a fluorine atom, analkyl group, a silyl group, and an amino group.

[13] The organic electroluminescent element as described in any one of[1] to [12], in which the molecular weight of the compound representedby any one of the general formulae (I) to (IV) is 800 or less.

[14] The organic electroluminescent element as described in any one of[1] to [13], in which the compound represented by any one of the generalformulae (I) to (IV) is contained in the light emitting layer.

[15] The organic electroluminescent element as described in [14], inwhich the compound represented by any one of the general formulae (I) to(IV) is a light emitting material contained in the light emitting layer.

[16] The organic electroluminescent element as described in [15],further including a host material in the light emitting layer.

[17] The organic electroluminescent element as described in [16], inwhich the host material has a hydrocarbon fused ring structure having 10to 50 carbon atoms.

[18] The organic electroluminescent element as described in [16], inwhich the host material has an anthracene skeleton.

[19] The organic electroluminescent element as described in any one of[1] to [18], in which the organic layer containing the compoundrepresented by any one of the general formulae (I) to (IV) is formed bya vacuum deposition process.

[20] The organic electroluminescent element as described in any one of[1] to [18], in which the light emitting layer is formed by a wetprocess.

[21] A light emitting device using the organic electroluminescentelement as described in any one of [1] to [20].

[22] A display device using the organic electroluminescent element asdescribed in any one of [1] to [20].

[23] An illumination device using the organic electroluminescent elementas described in any one of [1] to [20].

[24] A material for an organic electroluminescent element, which is acompound represented by the following general formula (V′).

[In the general formula (V′), R⁴¹ to R⁴⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁴¹ toR⁴⁷ are not bonded to each other to form a ring. R⁴⁸ to R⁵⁵ eachindependently represent a hydrogen atom or a substituent, and twoadjacent groups out of R⁴⁸ to R⁵⁵ may be bonded to each other to form aring. X⁴¹ and X⁴² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, and O. R⁶¹ to R⁶⁵ eachindependently represent a hydrogen atom or a substituent.]

[25] A material for an organic electroluminescent element, which isrepresented by the following general formula (VI′).

[In the general formula (VI′), R⁷¹ to R⁷⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁷¹ toR⁷⁷ are not bonded to each other to form a ring. R⁷⁸ to R⁸⁵ eachindependently represent a hydrogen atom or a substituent, and twoadjacent groups out of R⁷⁸ to R⁸⁵ may be bonded to each other to form aring. X^(5′) and X⁵² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, and O. R⁶¹ to R⁶⁵ eachindependently represent a hydrogen atom or a substituent.]

Advantageous Effects of Invention

The organic electroluminescent element of the present invention hasadvantageous effects of emitting dark blue light and exhibiting goodchromaticity at a wide range of concentrations of light emittingmaterials. Further, if the material for an organic electroluminescentelement of the present invention is used, such an excellent organicelectroluminescent element can be easily prepared. In addition, thelight emitting device, the display device, and the illumination deviceof the present invention have advantageous effects in that they have lowpower consumption and excellent chromaticity, and exhibit goodchromaticity even at a high concentration of the light emittingmaterial, and are suitable particularly in display applications.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing one example of a configuration of anorganic electroluminescent element according to the present invention.

FIG. 2 is a schematic view showing one example of a light emittingdevice according to the present invention.

FIG. 3 is a schematic view showing one example of a illumination deviceaccording to the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the details of the present invention will be described. Thedescription of the configuration requirements as described below isbased on representative embodiments and specific examples of the presentinvention, but the present invention is not limited to these embodimentsand specific examples. Incidentally, in the present specification, therange expressed with “to” means a range including the numerical valuesbefore and after “to” as the lower limit and the upper limit,respectively.

[Light Emitting Materials for Organic Electroluminescent Element,Represented by General Formulae (I) to (IV)]

The organic electroluminescent element of the present invention has atleast a substrate, a pair of electrodes including an anode and acathode, disposed on the substrate, and at least one organic layerincluding a light emitting layer, disposed between the electrodes. Theorganic electroluminescent element of the present invention contains atleast one kind of compound represented by any one of the followinggeneral formulae (I) to (IV) in any layers of the organic layers.

In the general formulae (I) to (IV), R¹ to R³⁷ each independentlyrepresent a hydrogen atom or a substituent, but two adjacent groups outof R¹ to R³⁷ are not bonded to each other to form a ring. X¹ to X³² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵ each independentlyrepresent a hydrogen atom or a substituent. A¹ to A³⁸ each independentlyrepresent CR⁶⁶ or N. R⁶⁶ represents a hydrogen atom or a substituent,and when two adjacent groups out of A¹ to A³⁸ are CR⁶⁶, the two R⁶⁶'smay be bonded to each other to form a ring structure.

In the organic electroluminescent element of the present invention, thecompound for an organic electroluminescent element, represented by anyone of the general formulae (I) to (IV) (hereinafter also referred to asa light emitting material represented by any one of the general formulae(I) to (IV), the light emitting material of the present invention, orthe compound of the present invention) is used as a light emittingmaterial.

The present inventors have found that it is possible to attainsufficient dark blue light emission, a change in the chromaticity afterdriving, and inhibition of an increase in the voltage afterdeterioration by decomposition by using pyrene with a fused ring, inwhich an aromatic ring is in contact at a position as shown by thegeneral formulae (I) to (IV). This is presumed to be due to a fact thatthe symmetry of the molecule is reduced by winding the ringsasymmetrically with respect to the center of pyrene to inhibit theassociation among the molecules as in the general formulae (I) to (IV).

On the other hand, if an organic electroluminescent element isfabricated using a pyrene-based compound in the related art and used fora long period of time, the chromaticity is changed due to deteriorationby driving with a lowered luminous intensity. It is thought that thecauses of the change in the chromaticity involved in such adeterioration by driving are a change in the light emitting positionsdue to a change in the element charge balance and optical interferencetherefrom, formation of association among pyrene rings by heatgeneration involved in driving, production of light emitting componentsby chemical reaction deterioration of the light emitting materials orhost materials by element driving, or the like. As a result, in order toprevent a change in the chromaticity involved in deterioration bydriving, it is necessary to provide materials which are insusceptible toany of those events. The compound represented by any one of the generalformulae (I) to (IV) of the present invention is stable against holes(oxidation) or electrons (reduction) and has a high charge injecting ortransporting property. With the compound, the association among thepyrene rings does not easily occur and the chemical reactiondeterioration by element driving does not easily occur. As a result, thechange in the chromaticity involved in deterioration by driving does noteasily occur, either. In addition, since the compound represented by anyone of the general formulae (I) to (IV) of the present invention isinsusceptible to association among the pyrene rings, it can form a lightemitting layer alone without the use of a host material.

Moreover, since the compound represented by any one of the generalformulae (I) to (IV) has a structure in which molecules are lessaccessible to each other, it can not only exhibit good blue lightemission, but also improve the chromaticity at a wide range ofconcentrations.

That is, the light emitting material for an organic electroluminescentelement, represented by any one of the general formulae (I) to (IV),contributes to shortening of the wavelength and inhibition of thechromaticity at a wide range of concentrations in its mother skeleton.From this, the light emitting material represented by any one of thegeneral formulae (I) to (IV) is not limited in the substituent of themother skeleton and provides the effects above. However, in a preferredaspect of the present invention, shortening of the wavelength andimprovement of the chromaticity at a wide range of concentrations may bepromoted by using a specific substituent.

Hereinbelow, the light emitting materials represented by the generalformulae (I) to (IV) will be described in detail.

In the general formulae (I) to (IV), X¹ to X³² each independentlyrepresent a linking group represented by any one of CR⁶¹R⁶², NR⁶³, O, S,and SiR⁶⁴R⁶⁵. The linking group is preferably CR⁶¹R⁶² or NR⁶³, from theviewpoint of luminous color.

X¹ and X² in the general formula (I) may be the same as or differentfrom each other. In the case where they are the same as each other, itis preferable that they be all CR⁶¹R⁶² or NR⁶³. In the case where theyare different from each other, preferred combinations may include a casewhere one is CR⁶¹R⁶² and the other is NR⁶³, a case where one is CR⁶¹R⁶²and the other is O, a case where one is CR⁶¹R⁶² and the other is S, acase where one is CR⁶¹R⁶² and the other is SiR⁶⁴R⁶⁵, a case where one isNR⁶³ and the other is O, a case where one is NR⁶³ and the other is S,and a case where one is O and the other is S. The relationship of X¹ andX² in the general formula (I) is also suitable for X¹¹ and X¹² in thegeneral formula (II), X²¹ and X²² in the general formula (III), and X³¹and X³² in the general formula (IV).

R⁶¹ to R⁶⁵ each independently represent a hydrogen atom or asubstituent. Examples of R⁶¹, R⁶², R⁶⁴ and R⁶⁵ include the followingSubstituent Group A and examples of R⁶³ include the followingSubstituent Group B.

<<Substituent Group A (Substituent on Carbon Atom and Substituent Groupon Silicon Atom)>>

An alkyl group (preferably having 1 to 30 carbon atoms, more preferablyhaving 1 to 20 carbon atoms, and particularly preferably having 1 to 10carbon atoms; for example, methyl, ethyl, isopropyl, t-butyl, n-octyl,n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, and cyclohexyl), analkenyl group (preferably having 2 to 30 carbon atoms, more preferablyhaving 2 to 20 carbon atoms, and particularly preferably having 2 to 10carbon atoms; for example, vinyl, allyl, 2-butenyl, and 3-pentenyl), analkynyl group (preferably having 2 to 30 carbon atoms, more preferablyhaving 2 to 20 carbon atoms, and particularly preferably having 2 to 10carbon atoms; for example, propargyl and 3-pentynyl), an aryl group(preferably having 6 to 30 carbon atoms, more preferably having 6 to 20carbon atoms, and particularly preferably having 6 to 12 carbon atoms;for example, phenyl, p-methylphenyl, naphthyl, anthranyl), amino group(preferably having 0 to 30 carbon atoms, more preferably having 0 to 20carbon atoms, and particularly preferably having 0 to 10 carbon atoms;for example, amino, methylamino, dimethylamino, diethylamino,dibenzylamino, diphenylamino, and ditolylamino), an alkoxy group(preferably having 1 to 30 carbon atoms, more preferably having 1 to 20carbon atoms, and particularly preferably having 1 to 10 carbon atoms;for example, methoxy, ethoxy, butoxy, and 2-ethylhexyloxy), and aryloxygroup (preferably having 6 to 30 carbon atoms, more preferably having 6to 20 carbon atoms, and particularly preferably having 6 to 12 carbonatoms; for example, phenyloxy, 1-naphthyloxy, and 2-naphthyloxy), aheterocyclic oxy group (preferably having 1 to 30 carbon atoms, morepreferably having 1 to 20 carbon atoms, and particularly preferablyhaving 1 to 12 carbon atoms; for example, pyridyloxy, pyrazyloxy,pyrimidyloxy, and quinolyloxy), an acyl group (preferably having 2 to 30carbon atoms, more preferably having 2 to 20 carbon atoms, andparticularly preferably having 2 to 12 carbon atoms; for example,acetyl, benzoyl, formyl, and pivaloyl), an alkoxycarbonyl group(preferably having 2 to 30 carbon atoms, more preferably having 2 to 20carbon atoms, and particularly preferably having 2 to 12 carbon atoms;for example, methoxycarbonyl and ethoxycarbonyl), an aryloxycarbonylgroup (preferably having 7 to 30 carbon atoms, more preferably having 7to 20 carbon atoms, and particularly preferably having 7 to 12 carbonatoms; for example, phenyloxycarbonyl), an acyloxy group (preferablyhaving 2 to 30 carbon atoms, more preferably having 2 to 20 carbonatoms, and particularly preferably having 2 to 10 carbon atoms; forexample, acetoxy and benzoyloxy), an acylamino group (preferably having2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, andparticularly preferably having 2 to 10 carbon atoms; for example,acetylamino and benzoylamino), an alkoxycarbonylamino group (preferablyhaving 2 to 30 carbon atoms, more preferably having 2 to 20 carbonatoms, and particularly preferably having 2 to 12 carbon atoms; forexample, methoxycarbonylamino), an aryloxycarbonylamino group(preferably having 7 to 30 carbon atoms, more preferably having 7 to 20carbon atoms, and particularly preferably having 7 to 12 carbon atoms;for example, phenyloxycarbonylamino), a sulfonylamino group (preferablyhaving 1 to 30 carbon atoms, more preferably having 1 to 20 carbonatoms, and particularly preferably having 1 to 12 carbon atoms; forexample, methanesulfonylamino and benzenesulfonylamino), a sulfamoylgroup (preferably having 0 to 30 carbon atoms, more preferably having 0to 20 carbon atoms, and particularly preferably having 0 to 12 carbonatoms; for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, andphenylsulfamoyl), a carbamoyl group (preferably having 1 to 30 carbonatoms, more preferably having 1 to 20 carbon atoms, and particularlypreferably having 1 to 12 carbon atoms; for example, carbamoyl,methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl), an alkylthiogroup (preferably having 1 to 30 carbon atoms, more preferably having 1to 20 carbon atoms, and particularly preferably having 1 to 12 carbonatoms; for example, methylthio and ethylthio), an arylthio group(preferably having 6 to 30 carbon atoms, more preferably having 6 to 20carbon atoms, and particularly preferably having 6 to 12 carbon atoms;for example, phenylthio), a heterocyclic thio group (preferably having 1to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, andparticularly preferably having 1 to 12 carbon atoms; for example,pyridylthio, 2-benzoimizolylthio, 2-benzoxazolylthio, and2-benzothiazolylthio), a sulfonyl group (preferably having 1 to 30carbon atoms, more preferably having 1 to 20 carbon atoms, andparticularly preferably having 1 to 12 carbon atoms; for example, mesyland tosyl), a sulfinyl group (preferably having 1 to 30 carbon atoms,more preferably having 1 to 20 carbon atoms, and particularly preferablyhaving 1 to 12 carbon atoms; for example, methanesulfinyl andbenzenesulfinyl), a ureido group (preferably having 1 to 30 carbonatoms, more preferably having 1 to 20 carbon atoms, and particularlypreferably having 1 to 12 carbon atoms; for example, ureido,methylureido, and phenylureido), phosphoramide group (preferably having1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, andparticularly preferably having 1 to 12 carbon atoms; for example,diethylphosphoramide and phenylphosphoramide), a hydroxy group,amercapto group, a halogen atom (for example, a fluorine atom, achlorine atom, a bromine atom, and an iodine atom), a cyano group, asulfo group, a carboxyl group, a nitro group, ahydroxamic group, asulfino group, a hydrazino group, an imino group, a heterocyclic group(inclusive of an aromatic heterocyclic group, which preferably has 1 to30 carbon atoms, and more preferably 1 to 12 carbon atoms and in whichexamples of the hetero atom include a nitrogen atom, an oxygen atom, asulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and atellurium atom; and specific examples thereof include pyridyl,pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl,imidazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, quinolyl,furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino,morpholino, pyrrolidyl, pyrrolidino, benzoxazolyl, benzoimidazolyl,benzothiazolyl, a carbazolyl group, an azepinyl group, and a silolylgroup), a silyl group (preferably having 3 to 40 carbon atoms, morepreferably having 3 to 30 carbon atoms, and particularly preferablyhaving 3 to 24 carbon atoms; for example, trimethylsilyl andtriphenylsilyl), a silyloxy group (preferably having 3 to 40 carbonatoms, more preferably having 3 to 30 carbon atoms, and particularlypreferably having 3 to 24 carbon atoms; for example, trimethylsilyloxyand triphenylsilyloxy), and a phosphoryl group (for example, adiphenylphosphoryl group and a dimethylphosphoryl group). Thesesubstituents may be further substituted, and examples of the additionalsubstituent include the groups selected from the Substituent Group A asdescribed above. Further, the substituent substituted with a substituentmay be further substituted, and examples of the additional substituentinclude the groups selected from the Substituent Group A as describedabove. In addition, the substituent substituted with the substituentsubstituted with a substituent may be further substituted, and examplesof the additional substituent include the groups selected from theSubstituent Group A as described above.

<<Substituent Group B (Group of Substituents at Nitrogen Atom)>>

An alkyl group (preferably having 1 to 30 carbon atoms, more preferablyhaving 1 to 20 carbon atoms, and particularly preferably having 1 to 10carbon atoms; for example, methyl, ethyl, isopropyl, t-butyl, n-octyl,n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, and cyclohexyl), analkenyl group (preferably having 2 to 30 carbon atoms, more preferablyhaving 2 to 20 carbon atoms, and particularly preferably having 2 to 10carbon atoms; for example, vinyl, allyl, 2-butenyl, and 3-pentenyl), analkynyl group (preferably having 2 to 30 carbon atoms, more preferablyhaving 2 to 20 carbon atoms, and particularly preferably having 2 to 10carbon atoms; for example, propargyl and 3-pentynyl), an aryl group(preferably having 6 to 30 carbon atoms, more preferably having 6 to 20carbon atoms, and particularly preferably having 6 to 12 carbon atoms;for example, phenyl, p-methylphenyl, naphthyl, and anthranyl), a cyanogroup, and a heterocyclic group (inclusive of an aromatic heterocyclicgroup, which preferably has 1 to 30 carbon atoms, and more preferably 1to 12 carbon atoms and in which examples of the hetero atom include anitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, asilicon atom, a selenium atom, and a tellurium atom; and specificexamples thereof include pyridyl, pyrazinyl, pyrimidyl, pyridazinyl,pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl,isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl,tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl,pyrrolidino, benzoxazolyl, benzoimidazolyl, benzothiazolyl, a carbazolylgroup, an azepinyl group, and a silolyl group). These substituents maybe further substituted, and examples of the additional substituentinclude the groups selected from the Substituent Group B as describedabove. Further, the substituent substituted with a substituent may befurther substituted, and examples of the additional substituent includethe groups selected from the Substituent Group B as described above. Inaddition, the substituent substituted with the substituent substitutedwith a substituent may be further substituted, and examples of theadditional substituent include the groups selected from the SubstituentGroup B as described above.

R⁶¹, R⁶², R⁶⁴ and R⁶⁵ preferably represent an alkyl group (morepreferably a linear, branched, or cyclic alkyl group having 1 to 10carbon atoms), an aryl group (more preferably an aryl group having 6 to14 carbon atoms), or a heteroaryl group (preferably a heteroaryl grouphaving 5 to 20 carbon atoms and containing at least any one of N, O, andS as a hetero atom). Among these, a linear or branched alkyl grouphaving 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbonatoms are more preferred. In addition, from the viewpoint of easiness ofsynthesis, it is preferable that R⁶¹ and R⁶² be the same as each other.

R⁶³ is preferably any one of a linear, branched, or cyclic alkyl grouphaving 1 to 10 carbon atoms, an aryl group having 6 to 50 carbon atoms,or a heteroaryl group having 5 to 20 carbon atoms and containing any oneor more of N, O, and S as a hetero atom, and more preferably any one ofan aryl group having 6 to 14 carbon atoms and a heteroaryl group having5 to 20 carbon atoms and containing any one or more of N, O, and S as ahetero atom.

In the general formulae (I) to (IV), A¹ to A³⁸ each independentlyrepresent CR⁶⁶ or N. R⁶⁶ represents a hydrogen atom or a substituent.Examples of the substituent of R⁶⁶ include the Substituent Group A asdescribed above. Examples of the preferred substituent of R⁶⁶ include analkyl group (more preferably a linear, branched, or cyclic alkyl grouphaving 1 to 10 carbon atoms), an aryl group (more preferably an arylgroup having 6 to 14 carbon atoms), a heteroaryl group (preferably aheteroaryl group having 5 to 20 carbon atoms and containing at least anyone of N, O, and S as a hetero atom), a di-substituted amino group (morepreferably a dialkylamino group or a diarylamino group; the preferredrange of the alkyl or aryl in this case is the same as the alkyl or arylas described above), a halogeno group (preferably a fluoro group), acyano group, and a nitro group, and more preferred examples of thesubstituent include an alkyl group having 1 to 6 carbon atoms. Further,such a substituent may be further substituted with any one or moresubstituents. When two adjacent groups out of A¹ to A³⁸ are CR⁶⁶, thetwo R⁶⁶'s may be bonded to each other to form a ring structure. The ringstructure thus formed may be any one of an aromatic ring, a heterocycle,and a non-aromatic ring.

In A¹ to A⁴ in the general formula (I), the number of N's is preferably0 to 2, 0 or 1, and particularly preferably 0. That is, a case where A¹to A⁴ are all CR⁶⁶ may be mentioned as a preferred example. Thepreferred ranges of A⁵ to A⁸ in the general formula (I), All to A¹⁴ inthe general formula (II), A¹⁵ to A¹⁸ in the general formula (II), A²¹ toA²⁴ in the general formula (III), A²⁵ to A²⁸ in the general formula(III), A³¹ to A³⁴ in the general formula (IV), and A³⁵ to A³⁸ thegeneral formula (IV) are also the same as the preferred ranges of A¹ toA⁴ in the general formula (I).

In the general formulae (I) to (IV), R¹ to R³⁷ each independentlyrepresent a hydrogen atom or a substituent, but two adjacent groups outof R¹ to R³⁷ are not bonded to each other to form a ring. As mentionedherein, examples of the substituent include the Substituent Group A asdescribed above. R¹ to R³⁷ preferably represent an alkyl group (morepreferably a linear, branched, or cyclic alkyl group having 1 to 10carbon atoms), an aryl group (more preferably an aryl group having 6 to14 carbon atoms), a heteroaryl group (preferably a heteroaryl grouphaving 5 to 20 carbon atoms and containing at least any one of N, O, andS as a hetero atom), a di-substituted amino group (more preferably adialkylamino group or a diarylamino group; the preferred range of thealkyl or aryl in this case is the same as the alkyl or aryl in R¹ toR⁸), a halogeno group (preferably a fluoro group), a cyano group, or anitro group. Further, such a substituent may be substituted with any oneor more substituents, and the preferred range of the substituent in thiscase is the same as the substituent in R¹ to R³⁷.

It is preferable that the compound represented by any one of the generalformulae (I) to (IV) have any one of a fluorine atom, an alkyl group, asilyl group, an amino group, and a phenyl group or nitrogen-containingaromatic 6-membered ring having these groups in the molecule from theviewpoint of inhibition of association light emission. Particularlypreferred specific examples of a fluorine atom, an alkyl group, a silylgroup, an amino group, and a phenyl group or nitrogen-containingaromatic 6-membered ring containing these groups in the molecule areshown below, but the present invention is not limited thereto.

It is preferable that one or more R¹ to R⁷ in the general formula (I) bea substituent represented by any one of the following general formulae.

Ar¹ and Ar² each independently represent an aryl group, Ar³ represent adivalent arylene group. Ar¹ and Ar² are preferably a substituted orunsubstituted phenyl or naphthyl, and more preferably a substituted orunsubstituted phenyl. Ar³ is preferably a substituted or unsubstitutedphenylene or naphthylene, more preferably a substituted or unsubstitutedphenylene, and most preferably a substituted or unsubstitutedp-phenylene. Further, it is also preferable that R¹ to R⁷ be asubstituted or unsubstituted aryl group represented by a structure otherthan the structures above. For example, examples of R¹ to R⁷ include anaryl group substituted with an alkyl group, and a polycyclic aryl groupwhich may have a hetero atom. R¹ to R⁷ may be all hydrogen atoms. 0 to 4groups out of R¹ to R⁷ are preferably substituents, 0 to 2 groups aremore preferably substituents, and 0 or 1 group is still more preferablya substituent.

The preferred substituents of R¹ to R⁷ in the general formula (I), R¹¹to R¹⁷ in the general formula (II), and R²¹ to R²⁷ in the generalformula (III) are the same as the preferred substituents of R¹ to R⁷ inthe general formula (I).

The compound represented by the general formula (I) or the generalformula (II) among the general formulae (I) to (IV) is preferred, andthe compound represented by the general formula (I) is more preferred.

First, the compound represented by the general formula (I) is preferablya compound represented by the following general formula (VI).

In the general formula (VI), R⁷¹ to R⁷⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁷¹ toR⁷⁷ are not bonded to each other to form a ring. R⁷⁸ to R⁸⁵ eachindependently represent a hydrogen atom or a substituent, and twoadjacent groups out of R⁷⁸ to R⁸⁵ may be bonded to each other to form aring. X⁵¹ and X⁵² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵each independently represent a hydrogen atom or a substituent.

The preferred ranges of R⁷¹ to R⁷⁷, X⁵¹, X⁵² and R⁶¹ to R⁶⁵ in thegeneral formula (VI) are the same as the preferred ranges of R¹ to R³⁷,X¹ to X³² and R⁶¹ to R⁶⁵ in the general formulae (I) to (IV). Thepreferred ranges of R⁷⁸ to R⁸⁵ in the general formula (VI) are the sameas the preferred ranges of R⁶⁶ in the general formulae (I) to (IV).

Furthermore, the general formula (VI) is preferably represented by thegeneral formula (VI′), the description of each group in the generalformula (VI′) is the same as the description of each group in thegeneral formula (VI), and the following aspects are more preferred.

In the general formula (VI), X⁶¹ and X⁶² preferably each independentlyrepresent a linking group represented by any one of CR⁶¹R⁶², NR⁶³, andO, and X⁶¹ and X⁶² are each independently represented by any one ofCR⁶¹R⁶², NR⁶³, and O, and X⁶¹ and X⁶² particularly preferably representdifferent linking groups.

In the general formula (VI), at least one of R⁷¹ to R⁸⁵ and R⁶¹ to R⁶⁵is more preferably a substituent having any of a fluorine atom, an alkylgroup, a silyl group, and an amino group, and examples of thesubstituent having any of a fluorine atom, an alkyl group, a silylgroup, and an amino group are the same as particularly preferredspecific examples of a fluorine atom, an alkyl group, a silyl group, anamino group, and a phenyl group or nitrogen-containing aromatic6-membered ring containing these groups in the molecule.

Moreover, the compound represented by the general formula (II) ispreferably a compound represented by the following general formula (V).

In the general formula (V), R⁴¹ to R⁴⁷ each independently represent ahydrogen atom or a substituent, but two adjacent groups out of R⁴¹ toR⁴⁷ are not bonded to each other to form a ring. R⁴⁸ to R⁵⁵ eachindependently represent a hydrogen atom or a substituent, two adjacentgroups out of R⁴⁸ to R⁵⁵ may be bonded to each other to form a ring. X⁴¹and X⁴² each independently represent a linking group represented by anyone of CR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵. R⁶¹ to R⁶⁵ each independentlyrepresent a hydrogen atom or a substituent.

The preferred ranges of R⁴¹ to R⁴⁷, X⁴¹, X⁴² and R⁶¹ to R⁶⁵ in thegeneral formula (V) are the same as the preferred ranges of R¹ to R³⁷,X¹ to X³² and R⁶¹ to R⁶⁵ in the general formulae (I) to (IV) above. Thepreferred ranges of R⁴⁸ to R⁵⁵ in the general formula (V) are the sameas the preferred ranges of R in the general formulae (I) to (IV).

Moreover, the general formula (V) is preferably represented by thegeneral formula (V′), the description of each group in the generalformula (V′) is the same as the description of each group in the generalformula (V), and the following aspects are more preferred.

In the general formula (V), it is more preferable that X⁵¹ and X⁵² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, and O, and it is particularly preferable that X⁵¹ and X⁵²each independently represented by any one of CR⁶¹R⁶², NR⁶³, and O, andX⁵¹ and X⁵² represent different linking groups.

In the general formula (V), it is more preferable that at least one ofR⁴¹ to R⁵⁵ and R⁶¹ to R⁶⁵ be a substituent having any one of a fluorineatom, an alkyl group, a silyl group, and an amino group, and examples ofthe substituent having any one of a fluorine atom, an alkyl group, asilyl group, and an amino group are the same as particularly preferredspecific examples of a fluorine atom, an alkyl group, a silyl group, anamino group, and a phenyl group or nitrogen-containing aromatic6-membered ring containing these groups in the molecule.

Specific examples of the light emitting material represented by any oneof the general formulae (I) to (IV) are shown below, but it should notbe construed that the light emitting material represented by the generalformulae (I) to (IV) which can be used in the present invention islimited to the specific examples.

The compounds represented by the general formulae (I) to (IV) can besynthesized by a combination of known reactions.

It is possible to synthesize the compounds represented by the generalformulae (I) to (IV) by, for example, the following scheme.

The synthesized compound is preferably purified by columnchromatography, recrystallization, or the like, and then purified bysublimation purification. By the sublimation purification, organicimpurities can be separated and inorganic salts, residual solvents, orthe like can be removed effectively.

When synthesized compounds represented by the general formulae (I) to(IV) are used as light emitting material, the maximum light emittingwavelength thereof is preferably less than 455 nm, more preferably 400nm or more and less than 460 nm, particularly preferably 420 nm or moreand less than 460 nm, still more preferably 430 nm or more and less than460 nm, and most preferably 440 nm or more and less than 460 nm.

[Organic Electroluminescent Element]

The organic electroluminescent element of the present invention includesa substrate, a pair of electrodes including an anode and a cathode,disposed on the substrate, and at least one organic layer including alight emitting layer, disposed between the electrodes, in which thelight emitting layer includes compounds represented by the generalformulae (I) to (IV).

The configuration of the organic electroluminescent element of thepresent invention is not particularly limited. FIG. 1 shows one exampleof the configuration of the organic electroluminescent element of thepresent invention. The organic electroluminescent element 10 in FIG. 1has an organic layer between a pair of electrodes (an anode 3 and acathode 9) on a substrate 2.

The element configuration of the organic electroluminescent element, thesubstrate, the cathode, and the anode are described in detail in, forexample, JP-A-2008-270736, and the detailed descriptions described inthis publication can be applied to the present invention.

Hereinafter, preferred aspects of the organic electroluminescent elementof the present invention will be described in detail in the order of thesubstrate, the electrodes, the organic layer, a protective layer, asealing enclosure, a driving method, a light emitting wavelength, andapplications.

<Substrate>

The organic electroluminescent element of the present invention has asubstrate.

The substrate used in the present invention is preferably a substratethat does not scatter or decay light emitted from the organic layer. Inthe case of an organic material, those having excellent heat resistance,dimensional stability, solvent resistance, electrical insulatingproperties, and processability are preferred.

<Electrode>

The organic electroluminescent element of the present invention has apair of electrodes including an anode and a cathode, disposed on thesubstrate.

In view of the properties of the light emitting element, at least oneelectrode of a pair of electrodes, the anode and the cathode, ispreferably transparent or semi-transparent.

(Anode)

The anode may be usually one having a function as an electrode ofsupplying holes into an organic layer, and is not particularly limitedin terms of its shape, structure, size, or the like. Further, dependingon the use and purpose of the light emitting element, the anode can besuitably selected from the known electrode materials. As describedabove, the anode is usually provided as a transparent anode.

(Cathode)

The cathode may be usually one having a function as an electrode ofinjecting electrons to an organic layer, and is not particularly limitedin terms of its shape, structure, size, or the like. Further, dependingon the use and purpose of the light emitting element, the cathode can besuitably selected from the known electrode materials

<Organic Layer>

The organic electroluminescent element of the present invention has atleast one organic layer including a light emitting layer, disposedbetween the electrodes, in which the organic layer includes the hostmaterial and at least one light emitting material represented by thegeneral formulae (I) to (IV).

The organic layer is not particularly limited and can be suitablyselected depending on the use and purpose of the organicelectroluminescent element. However, the organic layer is preferablyformed on the transparent electrode or the semi-transparent electrode.In that case, the organic layer is formed on the whole surface or onesurface of the transparent electrode or the semi-transparent electrode.

The shape, the size, the thickness, and the like of the organic layerare not particularly limited and can be suitably selected depending onthe purpose.

Hereinafter, the configuration of the organic layer, the method forforming an organic layer, preferred aspects of the respective layersconstituting the organic layer, and the materials used in the respectivelayers in the organic electroluminescent element of the presentinvention will be described in detail in order.

(Configuration of Organic Layer)

In the organic electroluminescent element of the present invention, theorganic layer includes a light emitting layer. The organic layerpreferably includes a charge transporting layer. The charge transportinglayer refers to a layer in which charges move when voltage is applied tothe organic electroluminescent element. Specifically, examples thereofinclude a hole injecting layer, a hole transporting layer, an electronblocking layer, a light emitting layer, a hole blocking layer, anelectron transporting layer, and an electron injecting layer. When thecharge transporting layer is a hole injecting layer, a hole transportinglayer, an electron blocking layer, or a light emitting layer, an organicelectroluminescent element can be prepared with low cost and highefficiency.

The compound represented by any one of the general formulae (I) to (IV)is contained in at least one layer out of one or a plurality of organiclayers disposed between the electrodes of the organic electroluminescentelement. In particular, the compound represented by any one of thegeneral formulae (I) to (IV) is preferably contained in a light emittinglayer. However, so far as the gist of the present invention is notdeviated, the compound represented by any one of the general formulae(I) to (IV) may be contained in an organic layer other than the lightemitting layer of the organic electroluminescent element of the presentinvention. Examples of the organic layer other than the light emittinglayer, which may contain the compound represented by any one of thegeneral formulae (I) to (IV), include a hole injecting layer, a holetransporting layer, an electron transporting layer, an electroninjecting layer, an exciton blocking layer, and a charge blocking layer(a hole blocking layer, an electron blocking layer, or the like),preferably any one of an exciton blocking layer, a charge blockinglayer, an electron transporting layer, and an electron injecting layer,and more preferably an exciton blocking layer, a charge blocking layer,or an electron transporting layer.

In the case where the compound represented by any one of the generalformulae (I) to (IV) is contained in the light emitting layer, thecompound represented by any one of the general formulae (I) to (IV) iscontained in the light emitting layer, preferably in the amount of 0.1%by mass to 100% by mass, more preferably 1% by mass to 50% by mass, andstill more preferably 2% by mass to 20% by mass, with respect to thetotal mass.

In the case where the compound represented by any one of the generalformulae (I) to (IV) is contained in an organic layer other than thelight emitting layer, the compound represented by any one of the generalformulae (I) to (IV) is contained in the light emitting layer,preferably in the amount of 70% by mass to 100% by mass, more preferably80% by mass to 100% by mass, and still more preferably 90% by mass to100% by mass, with respect to the total mass.

(Method for Forming Organic Layer)

The respective organic layers in the organic electroluminescent elementof the present invention can be suitably formed by any of dry filmforming methods such as a deposition method and a sputtering method, andwet type film forming methods (solution coating methods) such as atransfer method, a printing method, a spin coating method, and a barcoating method.

In the organic electroluminescent element of the present invention, theorganic layer disposed between the pair of electrodes is preferablyformed by a vacuum deposition process or a wet process. Further, thelight emitting layer is more preferably formed by deposition of acomposition further including at least the compound represented by anyone of the general formulae (I) to (IV).

(Light Emitting Layer)

The light emitting layer is a layer having a function of, uponapplication of an electric field, receiving holes from the anode, thehole injecting layer, or the hole transporting layer, receivingelectrons from the cathode, the electron injecting layer, or theelectron transporting layer, providing a recombination site of the holesand the electrons, and causing light emitting. However, the lightemitting layer in the present invention is not necessarily limited tothe light emitting by such a mechanism.

The light emitting layer in the organic electroluminescent element ofthe present invention may be constituted of only the light emittingmaterial, or may be constituted as a mixed layer of the host materialand the light emitting material. The light emitting material may be madeof a single kind or two or more kinds thereof. The host material ispreferably a charge transporting material. The host material may be madeof a single kind or two or more kinds thereof. Examples thereof includea configuration in which an electron transporting host material and ahole transporting host material are mixed. Further, the light emittinglayer may include a material which does not have charge transportingproperties and does not emit light.

In addition, the light emitting layer may be made of a single layer ormultiple layers of two or more layers. The respective layers may includethe same light emitting material or host material, and may also includea different material in every layer. In the case where a plurality oflight emitting layers are present, the respective light emitting layersmay emit light in a different luminous color from each other.

The thickness of the light emitting layer is not particularly limited,but it is usually from 2 nm to 500 nm, and above all, from the viewpointof external quantum efficiency, it is more preferably from 3 nm to 200nm, and still more preferably from 5 nm to 100 nm.

In the organic electroluminescent element of the present invention, thelight emitting layer contains the compound represented by any one of thegeneral formulae (I) to (IV), and it is a preferred aspect to use thecompound represented by any one of the general formulae (I) to (IV) as alight emitting material of the light emitting layer. Here, the hostmaterial as referred to in the present specification is a compound whichchiefly plays a role in injecting or transporting charges in the lightemitting layer and is also a compound which does not substantially emitlight in itself. As used herein, it is meant by the terms “which doesnot substantially emit light” that the amount of light emission from thecompound which does not substantially emit light is preferably 5% orless, more preferably 3% or less, and still more preferably 1% or less,with respect to the total amount of light emission in the whole of theelement. The compound represented by any one of the general formulae (I)to (IV) may be used as a host material of the light emitting layer.

(Light Emitting Material)

In the organic electroluminescent element of the present invention, thecompound represented by any one of the general formulae (I) to (IV) ispreferably used as the light emitting material, but in this case, acombination of the compound with light emitting materials different fromthe compound represented by any one of the general formulae (I) to (IV)can be used. Further, in the organic electroluminescent element of thepresent invention, in the case where the compound represented by any oneof the general formulae (I) to (IV) is used as a host material of thelight emitting layer or in the case where the compound represented byany one of the general formulae (I) to (IV) is used in an organic layerother than the light emitting layer, a light emitting material otherthan the compound represented by any one of the general formulae (I) to(IV) can be used in the light emitting layer.

The light emitting material which can be used in the present inventionmay be a fluorescent light emitting material. Further, the lightemitting layer in the present invention may contain two or more kinds oflight emitting materials in order to improve the color purity or widenthe light emitting wavelength region.

The fluorescent light emitting material which can be used in the organicelectroluminescent element of the present invention is described indetail in, for example, paragraph Nos. [0100] to [0164] ofJP-A-2008-270736 and paragraph Nos. [0088] to [0090] ofJP-A-2007-266458, the detailed descriptions thereon in thesepublications can be applied to the present invention.

The kind of the fluorescent light emitting material which can be used inthe present invention is not particularly limited, but examples thereofinclude those other than the compound represented by the generalformulae (1-1), for example, benzoxazole, benzimidazole, benzothiazole,styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene,naphthalimide, coumarin, pyrane, perinone, oxadiazole, aldazine,pyralizine, cyclopentadiene, bisstyrylanthracene, quinacridone,pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine,aromatic fused polycyclic compounds (anthracene, phenanthroline, pyrene,perylene, rubrene, pentacene, and the like), a variety of metalcomplexes typified by metal complexes of 8-quinolinol, pyrromethenecomplexes, and rare-earth complexes, polymer compounds such aspolythiophene, polyphenylene, and polyphenylenevinylene, organicsilanes, and derivatives thereof.

In addition, the compound described in [0082] of JP-A-2010-111620 canalso be used as a light emitting material.

The light emitting layer in the organic electroluminescent element ofthe present invention may be constituted with only a light emittingmaterial or may be constituted as a mixed layer of a host material and alight emitting material. The light emitting material may be made of asingle kind or two or more kinds. The host material is preferably acharge transport material. The host material may be made of a singlekind or two or more kinds. Examples thereof include a configuration inwhich an electron-transporting host material and a hole-transportinghost material are mixed. Furthermore, the light emitting layer maycontain a material which does not have charge transporting propertiesand which does not emit light.

In addition, the light emitting layer may be made of a single layer ortwo or more layers. The respective layers may include the same lightemitting materials or host materials, and may also include differentmaterials from each other over layers. In the case where a plurality oflight emitting layers are present, the respective light emitting layersmay emit light in different luminous colors from each other.

(Host Material)

The host material is a compound that usually plays a role in injectingor transporting charges in the light emitting layer and is also acompound which does not substantially emit light in itself. As usedherein, it is meant by the terms “which does not substantially emitlight” that the amount of light emitting from the compound which doesnot substantially emit light is preferably 5% or less, more preferably3% or less, and still more preferably 1% or less of the total amount oflight emitting in the whole of the element.

Examples of the host material which can be used in the organicelectroluminescent element of the present invention include thefollowing compounds:

conductive high-molecular oligomers such as pyrrole, indole, carbazole,azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole,imidazole, thiophene, benzothiophene, dibenzothiophene, furan,benzofuran, dibenzofuran, polyarylalkanes, pyrazoline, pyrazolone,phenylenediamine, arylamines, amino-substituted chalcone,styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatictertiary amine compounds, styrylamine compounds, porphyrin-basedcompounds, fused ring aromatic hydrocarbon compounds (fluorene,naphthalene, phenanthrene, triphenylene, and the like), polysilane-basedcompounds, poly(N-vinylcarbazole), aniline-based copolymers, thiopheneoligomers, and polythiophene, organic silanes, carbon films, pyridine,pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole,oxadiazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone,thiopyran dioxide, carbodiimide, fluorenylidenemethane,distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclictetracarboxylic anhydrides such as naphthalene perylene, phthalocyanine,and a variety of metal complexes typified by metal complexes of8-quinolinol derivatives and metal complexes having metalphthalocyanine, benzoxazole, or benzothiazole as a ligand thereof, andderivatives thereof (which may have a substituent or a fused ring). Inaddition, the compounds described in [0081] or [0083] ofJP-A-2010-111620 can also be used.

Above all, carbazole, dibenzothiophene, dibenzofuran, arylamine,aromatic hydrocarbon compounds with fused rings, and metal complexes arepreferred, and aromatic hydrocarbon compounds with fused rings areparticularly preferred since they are stable. As the aromatichydrocarbon compounds with fused rings, naphthalene-based compounds,anthracene-based compounds, phenanthrene-based compounds,triphenylene-based compounds, and pyrene-based compounds are preferred;anthracene-based compounds and pyrene-based compounds are morepreferred; and anthracene-based compounds are particularly preferred. Asthe anthracene-based compounds, those described in [0033] to [0064] ofWO 2010/134350 are particularly preferred, and examples thereof includeCompounds H-1 and H-2 as described later.

In the organic electroluminescent element of the present invention, thehost material included in the light emitting layer preferably has ahydrocarbon fused ring structure having 10 to 50 carbon atoms.

The hydrocarbon fused ring structure having 10 to 50 carbon atoms ispreferably naphthalene, phenanthrene, benzo[c]phenanthrene, anthracene,pyrene, triphenylene, or chrysene, more preferably naphthalene,phenanthrene, benzo[c]phenanthrene, or anthracene, and most preferablyanthracene. Specifically, the hydrocarbon fused ring structure having 10to 50 carbon atoms in the host material is further preferably ananthracene skeleton. Further, it is particularly preferable that thehydrocarbon fused ring structure having 10 to 50 carbon atoms is acompound composed of only carbon, and hydrogen or deuterium.

The host material that can be used in the light emitting layer in theorganic electroluminescent element of the present invention may be ahost material having hole transporting properties or a host materialhaving electron transporting properties.

In the light emitting layer, the singlet lowest excited energy (S₁energy) in the film state of the host material is preferably higher thanthe S₁ energy of the light emitting material from the viewpoints ofcolor purity, luminous efficiency, and driving durability. The S₁ of thehost material is preferably higher than the S₁ of the light emittingmaterial by 0.1 eV or more, more preferably by 0.2 eV or more, and stillmore preferably by 0.3 eV or more.

When S₁ in the film state of the host material is lower than S₁ of thelight emitting material, the light emitting is lost, and thus, the hostmaterial is required to have higher S₁ than the light emitting material.Further, even in the case where S₁ of the host material is higher thanthe light emitting material, a small difference in the S₁ of the bothleads to partial reverse energy movement from the light emittingmaterial to the host material, which causes reduction in efficiency,color purity, or durability. Therefore, there is a demand for a hostmaterial having a sufficiently high S₁, and high chemical stability andcarrier injecting/transporting properties.

Furthermore, the content of the host compound in the light emittinglayer in the organic electroluminescent element of the present inventionis not particularly limited, but from the viewpoint of luminousefficiency and driving voltage, it is preferably from 15% by mass to 95%by mass, with respect to the total mass of the compounds forming thelight emitting layer. When the light emitting layer includes a pluralityof kinds of host compounds containing the compound represented by anyone of the general formulae (I) to (IV), the content of the compoundrepresented by any one of the general formulae (I) to (IV) is preferablyfrom 50% by mass to 99% by mass, with respect to the total hostcompounds.

(Other Layers)

The organic electroluminescent element of the present invention mayinclude layers other than the light emitting layer.

Examples of the organic layer other than the light emitting layer whichmay be included in the organic layer include a hole injecting layer, ahole transporting layer, a blocking layer (a hole blocking layer, anexciton blocking layer, and the like), and an electron transportinglayer. Specifically, examples of the layer configuration include thosedescribed below, but it should not be construed that the presentinvention is limited to these configurations.

-   -   Anode/hole transporting layer/light emitting layer/electron        transporting layer/cathode,    -   Anode/hole transporting layer/light emitting layer/blocking        layer/electron transporting layer/cathode,    -   Anode/hole transporting layer/light emitting layer/blocking        layer/electron transporting layer/electron injecting        layer/cathode,    -   Anode/hole injecting layer/hole transporting layer/light        emitting layer/blocking layer/electron transporting        layer/cathode,    -   Anode/hole injecting layer/hole transporting layer/light        emitting layer/electron transporting layer/electron injecting        layer/cathode,    -   Anode/hole injecting layer/hole transporting layer/light        emitting layer/blocking layer/electron transporting        layer/electron injecting layer/cathode,    -   Anode/hole injecting layer/hole transporting layer/blocking        layer/light emitting layer/blocking layer/electron transporting        layer/electron injecting layer/cathode.

The organic electroluminescent element of the present inventionpreferably includes at least one organic layer which is preferablydisposed between the (A) anode and the light emitting layer. Examples ofthe organic layer which is preferably disposed between the (A) anode andthe light emitting layer include an hole injecting layer, a holetransporting layer, and an electron blocking layer from the anode side.

The organic electroluminescent element of the present inventionpreferably includes at least one organic layer which is preferablydisposed between the (B) cathode and the light emitting layer. Examplesof the organic layer which is preferably disposed between the (B)cathode and the light emitting layer include an electron injectinglayer, an electron transporting layer, and a hole blocking layer fromthe cathode side.

Specifically, an example of the preferred aspects of the organicelectroluminescent element of the present invention is the aspect shownin FIG. 1, in which a hole injecting layer 4, a hole transporting layer5, a light emitting layer 6, a hole blocking layer 7, and an electrontransporting layer 8 are laminated in this order as the organic layerfrom the anode 3 side.

Hereinafter, the layers other than the light emitting layer which theorganic electroluminescent element of the present invention may havewill be described.

(A) Organic Layer Preferably Disposed Between Anode and Light EmittingLayer:

First, the (A) organic layer preferably disposed between the anode andthe light emitting layer will be described.

(A-1) Hole Injecting Layer and Hole Transporting Layer

The hole injecting layer and the hole transporting layer are layershaving a function of receiving holes from the anode or the anode sideand transporting them to the cathode side.

The light emitting element of the present invention preferably includesat least one organic layer between the light emitting layer and theanode, and the organic layer preferably includes at least one compoundof the compounds represented by the following general formulae (Sa-1),(Sb-1), and (Sc-1).

(in which X represents a substituted or unsubstituted alkylene grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkenylenegroup having 2 to 30 carbon atoms, a substituted or unsubstitutedarylene group having 6 to 30 carbon atoms, a substituted orunsubstituted heteroarylene group having 2 to 30 carbon atoms, or asubstituted or unsubstituted heterocycle having 2 to 30 carbon atoms.R^(S1), R^(S2), and R^(S3) each independently represent a hydrogen atom,a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms,a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 carbon atoms,a substituted or unsubstituted heterocycle having 2 to 30 carbon atoms,a substituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms, a hydroxy group, a cyano group, or a substituted orunsubstituted amino group. Adjacent R^(S1), R^(S2), and R^(S3) may bebonded to each other to form a saturated carbocycle or an unsaturatedcarbocycle. Ar^(S1) and Ar^(S2) each independently represent asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, ora substituted or unsubstituted heteroaryl group having 2 to 30 carbonatoms.)

(in which R^(S4), R^(S5), R^(S6), and R^(S7) each independentlyrepresent a hydrogen atom, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms, a substituted or unsubstituted aryloxygroup having 6 to 30 carbon atoms, a substituted or unsubstitutedheterocycle having 2 to 30 carbon atoms, a substituted or unsubstitutedfused polycyclic group having 5 to 30 carbon atoms, a hydroxy group, acyano group, or a substituted or unsubstituted amino group. AdjacentR^(S4), R^(S5), R^(S6), and R^(S7) may be bonded to each other to form asaturated carbocycle or an unsaturated carbocycle. Ar^(S3) represents asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, ora substituted or unsubstituted heteroaryl group having 2 to 30 carbonatoms.)

(in which R^(S8) and R^(S9) each independently represent a hydrogenatom, a substituted or unsubstituted alkyl group having 1 to 30 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms, a substituted or unsubstituted heterocyclic group having 2 to 30carbon atoms, or a substituted or unsubstituted fused polycyclic grouphaving 5 to 30 carbon atoms. R^(S10) represents a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, a substituted orunsubstituted heterocyclic group having 2 to 30 carbon atoms, or asubstituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms. R^(S11) and R^(S12) each independently represent ahydrogen atom, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 carbon atoms, a substituted or unsubstituted heterocycle having 2 to30 carbon atoms, a substituted or unsubstituted fused polycyclic grouphaving 5 to 30 carbon atoms, a hydroxy group, a cyano group, or asubstituted or unsubstituted amino group. Adjacent R^(S11) and R^(S12)may be bonded to each other to form a saturated carbocycle or anunsaturated carbocycle. Ar^(S4) represents a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, or a substitutedor unsubstituted heteroaryl group having 2 to 30 carbon atoms. Y^(S1)and Y^(S2) each independently represent a substituted or unsubstitutedalkylene group having 1 to 30 carbon atoms, or a substituted orunsubstituted arylene group having 6 to 30 carbon atoms. n and m eachindependently represent an integer of 0 to 5.)

The general formula (Sa-1) will be described.

In the general formula (Sa-1), X represents a substituted orunsubstituted alkylene group having 1 to 30 carbon atoms, a substitutedor unsubstituted alkenylene group having 2 to 30 carbon atoms, asubstituted or unsubstituted arylene group having 6 to 30 carbon atoms,a substituted or unsubstituted heteroarylene group having 2 to 30 carbonatoms, or a substituted or unsubstituted heterocycle having 2 to 30carbon atoms. X is preferably a substituted or unsubstituted arylenegroup having 6 to 30 carbon atoms, more preferably having a substitutedor unsubstituted phenylene, a substituted or unsubstituted biphenylene,and a substituted or unsubstituted naphthylene, and still morepreferably a substituted or unsubstituted biphenylene.

R^(S1), R^(S2), and R^(S3) each independently represent a hydrogen atom,a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms,a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 carbon atoms,a substituted or unsubstituted heterocycle having 2 to 30 carbon atoms,a substituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms, a hydroxy group, a cyano group, or a substituted orunsubstituted amino group. Adjacent R^(S1), R^(S2), and R^(S3) may bebonded to each other to form a saturated carbocycle or an unsaturatedcarbocycle. Examples of the saturated carbocycle or the unsaturatedcarbocycle include naphthalene, azulene, anthracene, fluorene, andphenalene. R^(S1), R^(S2), and R^(S3) are preferably a hydrogen atom, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms, or a cyano group, and more preferably a hydrogen atom.

Ar^(S1) and Ar^(S2) each independently represent a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, or a substitutedor unsubstituted heteroaryl group having 2 to 30 carbon atoms. Ar^(S1)and Ar^(S2) are preferably a substituted or unsubstituted phenyl group.

Next, the general formula (Sb-1) will be described.

In the general formula (Sb-1), R^(S4), R^(S5), R^(S6) and R^(S7) eachindependently represent a hydrogen atom, a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 30 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 30 carbon atoms, a substituted orunsubstituted heterocycle having 2 to 30 carbon atoms, or a substitutedor unsubstituted fused polycyclic group having 5 to 30 carbon atoms, ahydroxy group, a cyano group, or a substituted or unsubstituted aminogroup. Adjacent R^(S4), R^(S5), R^(S6) and R^(S7) may be bonded to eachother to form a saturated carbocycle or an unsaturated carbocycle.Examples of the saturated carbocycle or the unsaturated carbocycleinclude naphthalene, azulene, anthracene, fluorene, and phenalene.R^(S4), R^(S5), R^(S6) and R^(S7) are preferably a hydrogen atom, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms, or a cyano group, and more preferably a hydrogen atom.

Ar^(S3) represents a substituted or unsubstituted aryl group having 6 to30 carbon atoms, or a substituted or unsubstituted heteroaryl grouphaving 2 to 30 carbon atoms. Ar^(S3) is preferably a substituted orunsubstituted phenyl group.

Next the general formula (Sc-1) will be described.

In the general formula (Sc-1), R^(S8) and R^(S9) each independentlyrepresent a hydrogen atom, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms, a substituted or unsubstituted heterocyclicgroup having 2 to 30 carbon atoms, or a substituted or unsubstitutedfused polycyclic group having 5 to 30 carbon atoms. R^(S8) and R^(S9)are preferably a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, or a substituted or unsubstituted aryl group having 6 to30 carbon atoms, and more preferably a methyl group or a phenyl group.R^(S10) is a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted heterocyclic group having 2to 30 carbon atoms, or a substituted or unsubstituted fused polycyclicgroup having 5 to 30 carbon atoms. R^(S10) is preferably a substitutedor unsubstituted aryl group having 6 to 30 carbon atoms, and morepreferably a phenyl group. R^(S11) and R^(S12) each independentlyrepresent a hydrogen atom, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms, a substituted or unsubstituted aryloxygroup having 6 to 30 carbon atoms, a substituted or unsubstitutedheterocycle having 2 to 30 carbon atoms, a substituted or unsubstitutedfused polycyclic group having 5 to 30 carbon atoms, a hydroxy group, acyano group, or a substituted or unsubstituted amino group. AdjacentR^(S11) and R¹² may be bonded to each other to form a saturatedcarbocycle or an unsaturated carbocycle. Examples of the saturatedcarbocycle or the unsaturated carbocycle include naphthalene, azulene,anthracene, fluorene, and phenalene. R^(S11) and R^(S12) are preferablya hydrogen atom, a substituted or unsubstituted alkyl group having 1 to30 carbon atoms, a substituted or unsubstituted aryl group having 6 to30 carbon atoms, a substituted or unsubstituted fused polycyclic grouphaving 5 to 30 carbon atoms, or a cyano group, and more preferably ahydrogen atom. Ar^(S4) represents a substituted or unsubstituted arylgroup having 6 to 30 carbon atoms, or a substituted or unsubstitutedheteroaryl group having 2 to 30 carbon atoms. Y^(S1) and Y^(S2)represent a substituted or unsubstituted alkylene having 1 to 30 carbonatoms, or substituted or unsubstituted arylene having 6 to 30 carbonatoms. Y^(S1) and Y^(S2) are preferably a substituted or unsubstitutedarylene having 6 to 30 carbon atoms, and more preferably a substitutedor unsubstituted phenylene. n is an integer of 0 to 5, preferably 0 to3, more preferably 0 to 2, and still more preferably 0. m is an integerof 0 to 5, preferably 0 to 3, more preferably 0 to 2, and still morepreferably 1.

The general formula (Sa-1) is preferably a compound represented by thefollowing general formula (Sa-2).

(in which R^(S1), R^(S2), and R^(S3) each independently represent ahydrogen atom, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 carbon atoms, a substituted or unsubstituted heterocycle having 2 to30 carbon atoms, a substituted or unsubstituted fused polycyclic grouphaving 5 to 30 carbon atoms, a hydroxy group, a cyano group, or asubstituted or unsubstituted amino group. Adjacent R^(S1), R^(S2), andR^(S3) may be bonded to each other to form a saturated carbocycle or anunsaturated carbocycle. Q^(Sa) each independently represent a hydrogenatom, a cyano group, a fluorine atom, an alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, an aryloxy group having 6 to 30 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted heterocycle having 2 to 30 carbon atoms, ora substituted or unsubstituted amino group.)

The general formula (Sa-2) will be described. R^(S1), R^(S2), and R^(S3)have the same definitions as those in the general formula (Sa-1), andtheir preferred ranges are also the same. Each Q^(Sa) independentlyrepresents a hydrogen atom, a cyano group, a fluorine atom, an alkoxygroup having 1 to 30 carbon atoms, a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms, an aryloxy group having 6 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted heterocycle having 2 to 30carbon atoms, or a substituted or unsubstituted amino group. Q^(Sa) ispreferably a hydrogen atom, a cyano group, a fluorine atom, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, ora substituted or unsubstituted aryl group having 6 to 30 carbon atoms,more preferably having a hydrogen atom or a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, and still more preferably ahydrogen atom.

The general formula (Sb-1) is preferably a compound represented by thefollowing general formula (Sb-2).

(in which R^(S4), R^(S5), R^(S6) and R^(S7) each independently representa hydrogen atom, a substituted or unsubstituted alkyl group having 1 to30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to30 carbon atoms, a substituted or unsubstituted aryl group having 6 to30 carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 carbon atoms, a substituted or unsubstituted heterocycle having 2to 30 carbon atoms, a substituted or unsubstituted fused polycyclicgroup having 5 to 30 carbon atoms, a hydroxy group, a cyano group, or asubstituted or unsubstituted amino group. Adjacent R^(S4), R^(S5),R^(S6) and R^(S7) may be bonded to each other to form a saturatedcarbocycle or an unsaturated carbocycle. Q^(Sb) represents a hydrogenatom, a cyano group, a fluorine atom, an alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, an aryloxy group having 6 to 30 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted heterocycle having 2 to 30 carbon atoms, ora substituted or unsubstituted amino group.)

The general formula (Sb-2) will be described. R^(S4), R^(S5), R^(S6) andR^(S7) have the same definitions as those in the general formula (Sb-1),and their preferred ranges are also the same. Q^(Sa) represents ahydrogen atom, a cyano group, a fluorine atom, an alkoxy group having 1to 30 carbon atoms, a substituted or unsubstituted alkyl group having 1to 30 carbon atoms, an aryloxy group having 6 to 30 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, asubstituted or unsubstituted heterocycle having 2 to 30 carbon atoms, ora substituted or unsubstituted amino group. Q^(Sa) is preferably ahydrogen atom, a cyano group, a fluorine atom, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, or a substitutedor unsubstituted aryl group having 6 to 30 carbon atoms, more preferablyhaving a hydrogen atom, or a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, and still more preferably a hydrogen atom.

The general formula (Sc-1) is preferably a compound represented by thefollowing general formula (Sc-2).

(in which R^(S8) and R^(S9) each independently represent a hydrogenatom, a substituted or unsubstituted alkyl group having 1 to 30 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms, a substituted or unsubstituted heterocyclic group having 2 to 30carbon atoms, or a substituted or unsubstituted fused polycyclic grouphaving 5 to 30 carbon atoms. R^(S10) represents a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, a substituted orunsubstituted heterocyclic group having 2 to 30 carbon atoms, or asubstituted or unsubstituted fused polycyclic group having 5 to 30carbon atoms. R^(S11) and R^(S12) each independently represent ahydrogen atom, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 carbon atoms, a substituted or unsubstituted heterocycle having 2 to30 carbon atoms, or a substituted or unsubstituted fused polycyclicgroup having 5 to 30 carbon atoms, a hydroxy group, a cyano group, or asubstituted or unsubstituted amino group. Adjacent R^(S11) and R^(S12)may be bonded to each other to form a saturated carbocycle or anunsaturated carbocycle. Q^(Sc) represents a hydrogen atom, a cyanogroup, a fluorine atom, an alkoxy group having 1 to 30 carbon atoms, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, anaryloxy group having 6 to 30 carbon atoms, a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, a substituted orunsubstituted heterocycle having 2 to 30 carbon atoms, or a substitutedor unsubstituted amino group.)

The general formula (Sc-2) will be described. R^(S8), R^(S9), R^(S10),R^(S11) and R^(S12) have the same definitions as those in the generalformula (Sc-1), and their preferred ranges are also the same. Q^(Sc)represents a hydrogen atom, a cyano group, a fluorine atom, an alkoxygroup having 1 to 30 carbon atoms, a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms, an aryloxy group having 6 to 30carbon atoms, a substituted or unsubstituted aryl group having 6 to 30carbon atoms, a substituted or unsubstituted heterocycle having 2 to 30carbon atoms, or a substituted or unsubstituted amino group. Q^(Sc) ispreferably a hydrogen atom, a cyano group, a fluorine atom, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, ora substituted or unsubstituted aryl group having 6 to 30 carbon atoms,more preferably having a hydrogen atom, or a substituted orunsubstituted aryl group having 6 to 30 carbon atoms, and still morepreferably a phenyl group.

Specific examples of the compounds represented by the general formulae(Sa-1), (Sb-1), and (Sc-1) include the following ones. However, thepresent invention is not limited to the following specific examples.

The compound represented by the general formula (Sa-1), (Sb-1), or(Sc-1) can be synthesized by the method described in JP-A-2007-318101.After the synthesis, purification is preferably carried out by columnchromatography, recrystallization, reprecipitation, or the like, andthen by sublimation purification. By the sublimation purification,organic impurities can be separated and inorganic salts, residualsolvents, moisture, or the like can be removed effectively.

In the light emitting element of the present invention, the compoundrepresented by the general formula (Sa-1), (Sb-1), or (Sc-1) ispreferably included in the organic layer between the light emittinglayer and the anode, and above all, it is more preferably included inthe layer on the anode side adjacent to the light emitting layer, and itis particularly preferably a hole transporting material included in thehole transporting layer.

The compound represented by the general formula (Sa-1), (Sb-1), or(Sc-1) is preferably contained in the amount of 70% by mass to 100% bymass, and more preferably 85% by mass to 100% by mass, with respect tothe total mass of the organic layer added.

With respect to the hole injecting layer and the hole transportinglayer, the detailed descriptions in paragraph Nos. [0165] to [0167] ofJP-A-2008-270736 can be applied to the present invention.

The hole injecting layer preferably contains an electron receptivedopant. By incorporating the electron receptive dopant in the holeinjecting layer, there are effects in which, for example, the holeinjecting properties are improved, the driving voltage is lowered, andthe efficiency is improved. The electron receptive dopant may be any oneof organic materials and inorganic materials as long as it is capable ofwithdrawing electrons from a material to be doped and generating radicalcations, and examples thereof include tetracyanoquinodimethane (TCNQ),tetrafluorotetracyanoquinodimethane (F₄-TCNQ), and molybdenum oxide.

The electron receptive dopant in the hole injecting layer is containedin the amount of preferably from 0.01% by mass to 50% by mass, morepreferably from 0.1% by mass to 40% by mass, and still more preferablyfrom 0.2% by mass to 30% by mass, with respect to the total mass of thecompounds forming the hole injecting layer

(A-2) Electron Blocking Layer

The electron blocking layer is a layer having a function of preventingthe electrons, which have been transported from the cathode side to thelight emitting layer, from passing through to the anode side. In thepresent invention, the electron blocking layer can be provided as anorganic layer adjacent to the light emitting layer on the anode side.

As the organic compound constituting the electron blocking layer, forexample, those exemplified above as the hole transporting material canbe used.

The thickness of the electron blocking layer is preferably from 1 nm to500 nm, more preferably from 3 nm to 100 nm, and still more preferablyfrom 5 nm to 50 nm.

The electron blocking layer may have either a single layer structurecomposed of one or two or more kinds of materials selected from theabove-exemplified materials or a multilayer structure composed of aplurality of layers having the same composition or differentcompositions.

The material used in the electron blocking layer preferably has higherS₁ energy than that of the light emitting material from the viewpointsof color purity, luminous efficiency, and driving durability. The S inthe film state of the material used in the electron blocking layer ispreferably higher than the S₁ of the light emitting material by 0.1 eVor more, more preferably by 0.2 eV or more, and still more preferably by0.3 eV or more.

(B) Organic Layer Preferably Disposed Between Cathode and Light EmittingLayer

Next, the (B) organic layer preferably disposed between the cathode andthe light emitting layer will be described.

(B-1) Electron Injecting Layer and Electron Transporting Layer

The electron injecting layer and the electron transporting layer arelayers having a function of receiving electrons from the cathode or thecathode side and transporting them to the anode side. The electroninjecting material and the electron transporting material used in theselayers may be either a low-molecular compound or a high-molecularcompound.

As the electron transporting material, for example, the compoundrepresented by any one of the general formulae (I) to (IV) can be used.As the other electron transporting materials, any one selected fromaromatic ring tetracarboxylic acid anhydrides, such as pyridinederivatives, quinoline derivatives, pyrimidine derivatives, pyrazinederivatives, phthalazine derivatives, phenanthroline derivatives,triazine derivatives, triazole derivatives, oxazole derivatives,oxadiazole derivatives, imidazole derivatives, benzimidazolederivatives, imidazopyridine derivatives, fluorenone derivatives,anthraquinodimethane derivatives, anthrone derivatives, diphenylquinonederivatives, thiopyranedioxide derivatives, carbodiimide derivatives,fluorenylidenemethane derivatives, distyrylpyrazine derivatives,naphthalene, and perylene; various metal complexes typified by metalcomplexes of phthalocyanine derivatives or 8-quinolinol derivatives andmetal complexes having metal phthalocyanine, benzoxazole, orbenzothiazole as a ligand thereof, organic silane derivatives typifiedby silole, hydrocarbon compounds with fused rings, such as naphthalene,anthracene, phenanthrene, triphenylene, and pyrene is preferred, and anyone selected from pyridine derivatives, benzimidazole derivatives,imidazopyridine derivatives, metal complexes, and hydrocarbon compoundswith fused rings is more preferred.

From the viewpoint of decreasing the driving voltage, the thickness ofeach of the electron injecting layer and the electron transporting layeris preferably 500 nm or less.

The thickness of the electron transporting layer is preferably from 1 nmto 500 nm, more preferably from 5 nm to 200 nm, and still morepreferably from 10 nm to 100 nm. In addition, the thickness of theelectron injecting layer is preferably from 0.1 nm to 200 nm, morepreferably from 0.2 nm to 100 nm, and still more preferably from 0.5 nmto 50 nm.

The electron injecting layer and the electron transporting layer mayhave either a single layer structure composed of one or two or morekinds of the above-described materials or a multilayer structurecomposed of a plurality of layers having the same composition ordifferent compositions.

The electron injecting layer preferably contains an electron donatingdopant. By incorporating the electron donating dopant in the electroninjecting layer, there are effects that, for example, the electroninjecting properties are improved, the driving voltage is lowered, andthe efficiency is improved. The electron donating dopant may be any oneof organic materials and inorganic materials as long as it is capable ofgiving electrons to the material to be doped and generating radicalanions, and examples thereof include dihydroimidazole compounds such astetrathiafulvalene (TTF), tetrathianaphthacene (TTT), andbis-[1,3-diethyl-2-methyl-1,2-dihydrobenzimidazolyl], lithium, andcesium.

The electron donating dopant in the electron injecting layer iscontained in the amount of preferably from 0.01% by mass to 50% by mass,more preferably from 0.1% by mass to 40% by mass, and still morepreferably 0.5% by mass to 30% by mass, with respect to the total massof the compounds forming the electron injecting layer.

(B-2) Hole Blocking Layer

The hole blocking layer is a layer having a function of preventingholes, which have been transported from the anode side to the lightemitting layer, from passing through to the cathode side. In the presentinvention, the hole blocking layer can be provided as an organic layeradjacent to the light emitting layer on the cathode side.

In order that the S₁ energy of the organic compound in the film stateconstituting the hole blocking layer prevents the energy movement ofexcitons produced in the light emitting layer, and thus, does not lowerthe luminous efficiency, it is preferably higher than S₁ energy of thelight emitting material.

As an example of the organic compound constituting the hole blockinglayer, for example, the compound represented by any one of the generalformulae (I) to (IV) can be used.

Examples of the organic compounds constituting the hole blocking layer,other than the compound represented by any one of the general formulae(I) to (IV), include aluminum complexes such as aluminum (III)bis(2-methyl-8-quinolinato) 4-phenylphenolate (abbreviated as Balq),triazole derivatives, and phenanthroline derivatives such as2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated as BCP).

The thickness of the hole blocking layer is preferably from 1 nm to 500nm, more preferably from 3 nm to 100 nm, and still more preferably from5 nm to 50 nm.

The hole blocking layer may have either a single layer structurecomposed of one or two or more kinds of the above-described materials ora multilayer structure composed of a plurality of layers having the samecomposition or different compositions.

The material used in the hole blocking layer preferably has higher S₁energy than that of the light emitting material from the viewpoints ofcolor purity, luminous efficiency, and driving durability. The S₁ in thefilm state of the material used in the hole blocking layer is preferablyhigher than the S₁ of the light emitting material by 0.1 eV or more,more preferably by 0.2 eV or more, and still more preferably by 0.3 eVor more.

(B-3) Material which is Particularly Preferably Used in Organic Layer,Preferably Disposed Between Cathode and Light Emitting Layer

For the organic electroluminescent element of the present invention,examples of the material which is particularly preferably used in the(B) materials for an organic layer, preferably disposed between thecathode and the light emitting layer include the compound represented byany one of the general formulae (I) to (IV), a compound represented bythe following general formula (P-1), and a compound represented by thefollowing general formula (O-1).

Hereinafter, a compound represented by the general formula (O-1) and acompound represented by the general formula (P-1) will be described.

The organic electroluminescent element of the present inventionpreferably includes at least one organic layer between the lightemitting layer and the cathode, and the organic layer preferablycontains at least one of compounds represented by the following generalformula (O-1), from the viewpoint of efficiency or driving voltage of anelement. Hereinafter, the general formula (O-1) will be described.

(In the general formula (O-1), R⁰¹ represents an alkyl group, an arylgroup, or a heteroaryl group. A⁰¹ to A⁰⁴ each independently representC—R^(A) or a nitrogen atom. R^(A) represents a hydrogen atom, an alkylgroup, an aryl group, or a heteroaryl group, and a plurality of R^(A)'smay be the same as or different from each other. L⁰¹ represents any ofdivalent to hexavalent linking groups with an aryl ring or a heteroarylring. n⁰¹ represents an integer of 2 to 6).

R⁰¹ represents an alkyl group (preferably having 1 to 8 carbon atoms),an aryl group (preferably having 6 to 30 carbon atoms), or a heteroarylgroup (preferably having 4 to 12 carbon atoms), which may have asubstituent selected from the above-described Substituent Group A. R⁰¹is preferably an aryl group or a heteroaryl group, and more preferablyan aryl group. Preferred examples of the substituent in the case wherethe aryl group of R⁰¹ has a substituent include an alkyl group, an arylgroup, and a cyano group, more preferably an alkyl group and an arylgroup, and still more preferably an aryl group. In the case where thearyl group of R⁰¹ has a plurality of substituents, the plurality ofsubstituents may be bonded to each other to form a 5- or 6-memberedring. The aryl group of R⁰¹ is preferably a phenyl group which may havea substituent selected from Substituent Group A, more preferably aphenyl group which may be substituted with an alkyl group or an arylgroup, and still more preferably an unsubstituted phenyl group or2-phenylphenyl group.

A⁰¹ to A⁰⁴ each independently represent C—R^(A) or a nitrogen atom. Itis preferable that 0 to 2 groups out of A⁰¹ to A⁰⁴ be nitrogen atoms;and it is more preferable that 0 or 1 member out of A⁰¹ to A⁰⁴ benitrogen atoms. It is preferable that all of A⁰¹ to A⁰⁴ be C—R^(A), orA⁰¹ be a nitrogen atom, and A⁰² to A⁰⁴ are C—R^(A); it is morepreferable that A⁰¹ be a nitrogen atom, and A⁰² to A⁰⁴ be C—R^(A); it isstill more preferable that A⁰¹ be a nitrogen atom, A⁰² to A⁰⁴ beC—R^(A), and R^(A)'s be all hydrogen atoms.

R^(A) represents a hydrogen atom, an alkyl group (preferably having 1 to8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms),or a heteroaryl group (preferably having 4 to 12 carbon atoms), and mayhave a substituent selected from the above-described Substituent GroupA. Further, a plurality of R^(A)'s may be the same as or different fromeach other. R^(A) is preferably a hydrogen atom or an alkyl group, andmore preferably a hydrogen atom.

L⁰¹ represents any of a divalent to hexavalent linking group includingan aryl ring (preferably having 6 to 30 carbon atoms) or a heteroarylring (preferably having 4 to 12 carbon atoms.) L⁰¹ is preferably anarylene group, a heteroarylene group, an aryltriyl group, or aheteroaryltriyl group, more preferably a phenylene group, a biphenylenegroup, or a benzenetriyl group, and still more preferably a biphenylenegroup or a benzenetriyl group. L⁰¹ may have a substituent selected fromthe above-described Substituent Group A, and in a case of having thesubstituent, the substituent is preferably an alkyl group, an arylgroup, or a cyano group. Specific examples of L⁰¹ include the following.

n⁰¹ represents an integer of 2 to 6, preferably an integer of 2 to 4,and more preferably 2 or 3. n⁰¹ is most preferably 3 from the viewpointof the efficiency of an element, or most preferably 2 from the viewpointof the durability of an element.

The glass transition temperature (Tg) of the compound represented by thegeneral formula (O-1) is preferably from 100° C. to 300° C., morepreferably from 120° C. to 300° C., and still more preferably from 140°C. to 300° C., from the viewpoint of stability at the time of storage ata high temperature, or stable operation during driving at a hightemperature or against heat generation during driving.

Specific examples of the compound represented by the general formula(O-1) are shown below, but the compound represented by the generalformula (O-1), which can be used in the present invention, should not beconstrued to be limited to the specific examples.

The compound represented by the general formula (O-1) can be synthesizedby the method described in JP-A-2001-335776. After the synthesis,purification is preferably carried out by column chromatography,recrystallization, reprecipitation, or the like, and then by sublimationpurification. By the sublimation purification, organic impurities can beseparated and inorganic salts, residual solvents, moisture, or the likecan be removed effectively.

In the organic electroluminescent element of the present invention, thecompound represented by the general formula (O-1) is preferably includedin the organic layer between the light emitting layer and the cathode,however, it is more preferably included in the layer on the cathode sideadjacent to the light emitting layer.

The compound represented by the general formula (O-1) is preferablycontained in the amount of 70% by mass to 100% by mass, and morepreferably 85% by mass to 100% by mass, with respect to the total massof the organic layer added.

The organic electroluminescent element of the present inventionpreferably includes at least one layer of organic layers between thelight emitting layer and the cathode, and it is preferable that theorganic layer contain at least one of compounds represented by thefollowing general formula (P), from the viewpoint of efficiency or thedriving voltage of an element. Hereinafter, the general formula (P) willbe described.

(In the general formula (P), R^(P) represents an alkyl group (preferablyhaving 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbonatoms), which may have a substituent selected from the above-describedSubstituent Group A. nP represents an integer of 1 to 10, and in thecase where there are a plurality of R^(P)'s, these may be the same as ordifferent from each other. At least one of R^(P)'s is a substituentrepresented by the following general formulae (P-1) to (P-3).

(In the general formulae (P-1) to (P-3), R^(P1) to R^(P3) and R′^(P1) toR′^(P3) each represent an alkyl group (preferably having 1 to 8 carbonatoms), an aryl group (preferably having 6 to 30 carbon atoms), or aheteroaryl group (preferably having 4 to 12 carbon atoms), which mayhave a substituent selected from the above-described Substituent GroupA. n^(P1) and n^(P2) represent an integer of 0 to 4, and in the casewhere there are a plurality of R^(P1) to R^(P3) and R′^(P1) to R′^(P3),these may be the same as or different from each other. L^(P1) to L^(P)3represent any one of divalent linking groups consisting of a singlebond, an aryl ring, or a heteroaryl ring. * represents a bindingposition with the anthracene ring of the general formula (P)).

A preferred substituent other than the substituents represented by (P-1)to (P-3) as R^(P) is an aryl group, more preferably any one of a phenylgroup, a biphenyl group, a terphenyl group, and a naphthyl group, andstill more preferably a naphthyl group.

R^(P1) to R^(P3) and R′^(P1) to R′^(P3) are preferably any one of anaryl group and a heteroaryl group, more preferably an aryl group, stillmore preferably any one of a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group, and most preferably a phenyl group.

L^(P1) to L^(P3) are preferably any one of divalent linking groupsconsisting of a single bond and an aryl ring, more preferably any one ofa single bond, phenylene, biphenylene, terphenylene, and naphthylene,and still more preferably any one of a single bond, phenylene, andnaphthylene.

Specific examples of the compound represented by the general formula (P)are shown below, but the compound represented by the general formula (P)that can be used in the present invention should not be construed to belimited to the specific examples.

The compound represented by the general formula (P) can be synthesizedby the method described in WO 2003/060956 and WO 2004/080975. After thesynthesis, purification is preferably carried out by columnchromatography, recrystallization, reprecipitation, or the like, andthen by sublimation purification. By the sublimation purification,organic impurities can be separated and inorganic salts, residualsolvents, moisture, or the like can be removed effectively.

In the organic electroluminescent element of the present invention, thecompound represented by the general formula (P) is preferably includedin the organic layer between the light emitting layer and the cathode,and more preferably in the layer adjacent to the cathode.

The compound represented by the general formula (P) is preferablycontained in the amount of 70% by mass to 100% by mass, and morepreferably 85% by mass to 100% by mass, based on the total mass of theorganic layer added.

Preferred examples of the material other than the material used in theelectron injecting layer or the electron transporting layer in theorganic electroluminescent element of the present invention includesilole compounds described in JP-A-9-194487 or the like, phosphineoxidecompounds described in JP-A-2006-73581 or the like, nitrogen-containingaromatic 6-membered ring hetero compounds described in JP-A-2005-276801,JP-A-2006-225320, WO 2005/085387, or the like, compounds havingnitrogen-containing aromatic 6-membered hetero structures and carbazolestructures, described in WO 2003/080760, WO 2005/085387, or the like,and aromatic hydrocarbon compounds described in US2009/0009065, WO2010/134350, JP-T-2010-535806 (naphthalene compounds, anthracenecompounds, triphenylene compounds, phenanthrene compounds, pyrenecompounds, fluoranthene compounds, and the like).

<Protective Layer>

In the present invention, the entirety of the organic electroluminescentelement may be protected by a protective layer.

For the protective layer, the detailed description in paragraph Nos.[0169] to [0170] of JP-A-2008-270736 can also be applied to the presentinvention. Incidentally, the materials for the protective layer may beeither an inorganic material or an organic material.

<Sealing Enclosure>

For the organic electroluminescent element according to the presentinvention, the entirety of the element may be sealed using a sealingenclosure.

For the sealing enclosure, the detailed description in paragraph No.[0171] of JP-A-2008-270736 can be applied to the present invention.

<Driving Method>

The organic electroluminescent element of the present invention can emitlight by applying a direct current (it may contain an alternate currentcomponent, if necessary) voltage (typically from 2 volts to 15 volts) ora direct current between the anode and the cathode.

As a driving method of the organic electroluminescent element of thepresent invention, driving methods described in JP-A-2-148687,JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234685, andJP-A-8-241047, Japanese Patent No. 2784615, and U.S. Pat. Nos. 5,828,429and 6,023,308 can be applied.

The external quantum efficiency of the organic electroluminescentelement of the present invention is preferably 5% or more, morepreferably 6% or more, and still more preferably 7% or more. As to thenumerical value of the external quantum efficiency, a maximum value ofthe external quantum efficiency obtained when the organicelectroluminescent element is driven at 20° C., or a value of theexternal quantum efficiency in the vicinity of from 300 cd/m² to 400cd/m² obtained when the element is driven at 20° C. can be employed.

The internal quantum efficiency of the organic electroluminescentelement of the present invention is preferably 30% or more, morepreferably 50% or more, and still more preferably 70% or more. Theinternal quantum efficiency of the element is calculated by dividing theexternal quantum efficiency by the light extraction efficiency. Thelight extraction efficiency in usual organic EL elements is about 20%,but by taking into consideration the shape of a substrate, the shape ofan electrode, the thickness of an organic layer, the thickness of aninorganic layer, the refractive index of an organic layer, therefractive index of an inorganic layer, or the like, it is possible toincrease the light extraction efficiency to 20% or more.

<Light Emitting Wavelength>

In the organic electroluminescent element of the present invention, itslight emitting wavelength is the same as the maximum light emittingwavelength of the material for the organic electroluminescent element ofthe present invention, and the element is used for blue light emissionamong the three primary colors of light. In particular, in the organicelectroluminescent element of the present invention, the compoundrepresented by any one of the general formulae (I) to (IV) is subjectedto blue light emission as the light emitting material.

<Use of Organic Electroluminescent Element of the Present Invention>

The organic electroluminescent element of the present invention can besuitably used for display elements, displays, backlights,electrophotography, illumination light sources, recording light sources,exposure light sources, readout light sources, signs, billboards,interior decorations, optical communications, and the like, andparticularly preferably for devices driven in a region of high-intensityluminescence, such as a light emitting device, an illumination device,and a display device.

[Light Emitting Device]

The light emitting device of the present invention may include theorganic electroluminescent element of the present invention.

Next, the light emitting device of the present invention will bedescribed with reference to FIG. 2.

The light emitting device of the present invention is formed by usingthe organic electroluminescent element.

FIG. 2 is a cross-sectional view schematically showing one example ofthe light emitting device of the present invention. The light emittingdevice 20 in FIG. 2 includes a transparent substrate 2 (supportingsubstrate), an organic electroluminescent element 10, a sealingenclosure 16, and the like.

The organic electroluminescent element 10 is formed by laminating on thesubstrate 2 an anode 3 (first electrode), an organic layer 11, and acathode 9 (second electrode) in this order. In addition, a protectivelayer 12 is laminated on the cathode 9, and a sealing enclosure 16 isfurther provided via an adhesive layer 14 on the protective layer 12.Incidentally, a part of each of the electrodes 3 and 9, a diaphragm, aninsulating layer, and the like are omitted in FIG. 2.

Here, a photocurable adhesive such as an epoxy resin, or a thermosettingadhesive can be used for the adhesive layer 14, and for example, athermosetting adhesive sheet may also be used as the adhesive layer 14.

The light emitting device of the present invention is not particularlylimited in its use, and it can be used as not only an illuminationdevice but also a display device of a television set, a personalcomputer, a mobile phone, electronic paper, or the like.

[Illumination Device]

The illumination device of the present invention includes the organicelectroluminescent element of the present invention.

Next, the illumination device of the present invention will be describedwith reference to FIG. 3.

FIG. 3 is a cross-sectional view schematically showing one example ofthe illumination device of the present invention. The illuminationdevice 40 of the present invention includes, as shown in FIG. 3, theabove-described organic EL element 10 and a light scattering member 30.More specifically, the illumination device 40 is configured such thatthe substrate 2 of the organic EL element 10 and the light scatteringmember 30 are in contact with each other.

The light scattering member 30 is not particularly limited as long as itcan scatter light, but in FIG. 3, a member obtained by dispersing fineparticles 32 in a transparent substrate 31 is used. Suitable examples ofthe transparent substrate 31 include a glass substrate, and suitableexamples of the fine particles 32 include transparent resin fineparticles. As the glass substrate and the transparent resin fineparticles, a known product can be used for both. In such an illuminationdevice 40, when light emitted from the organic electroluminescentelement 10 is incident on the light incident surface 30A of thescattering member 30, the incident light is scattered by the lightscattering member 30 and the scattered light is output as illuminatinglight from the light output surface 30B.

[Display Device]

The display device of the present invention may include the organicelectroluminescent element of the present invention.

The display device of the present invention may be used for, forexample, a display device of a television set, a personal computer, amobile phone, electronic paper, or the like.

EXAMPLES

The characteristic features of the present invention are hereunderdescribed in more detail with reference to the following Examples andComparative Examples. The materials, use amounts, ratios, treatmentdetails, treatment procedures, and the like shown in the followingExamples and Comparative Examples can be appropriately modified so faras the gist of the present invention is not deviated. Accordingly, itshould not be construed that the scope of the present invention islimited to the specific examples shown below.

The structural formulae of the compounds used in Examples andComparative Examples are summarized below.

1. Synthesis Example

The compound represented by any one of the general formulae (I) to (IV)can be synthesized by the method described in the present specificationor a combination of other known reactions. Representative examples ofthe specific synthesis procedure of the compound represented by thegeneral formula (I) out of the compounds represented by any of thegeneral formulae (I) to (IV) will be described below.

(Synthesis Example 1) Synthesis of Compound 1

A synthesis intermediate 5 was synthesized according to the synthesisscheme with reference to well-known literatures. For the synthesis ofthe synthesis intermediate 3, reference may be made to [J. Am. Chem.Soc. 2006, 128, 581-590], and for the synthesis of the synthesisintermediate 5, reference may be made to JP-A-2010-111620. Subsequently,a compound 1 was synthesized by the following method.

520 mg (1.12 mmol) of synthesis intermediate 5, 414 mg (2.24 mmol) of1-bromo-3,5-dimethylbenzene, 51.2 mg (0.056 mmol) oftris(dibenzylideneacetone)dipalladium, 33.4 mg (0.112 mmol) of2-(di-t-butylphosphino)biphenyl, 324 mg (3.36 mmol) of t-butoxysodium,and 20 mL of xylene were mixed, and heated and refluxed for 1 hour and ahalf under a nitrogen atmosphere. The reaction liquid was returned toroom temperature and the solvent was evaporated. The residue waspurified by silica gel column chromatography (developing solvent:hexane/toluene (9:1)), and further purified by carrying outrecrystallization with toluene/IPA (1:5) twice to obtain 600 mg of thecompound 1 (yield 68%).

¹H NMR (400 MHz, in DMSO-d6); δ (ppm)=9.25 (s, 1H), 8.76 (d, 1H), 8.55(s, 1H), 8.54 (s, 1H), 8.36-8.34 (m, 1H), 8.22 (d, 1H), 7.96 (d, 1H),7.86-7.84 (m, 1H), 7.67 (d, 1H), 7.65-7.62 (m, 1H), 7.43-7.41 (m, 2H),7.38 (s, 1H), 7.30 (s, 2H), 7.19 (d, 1H), 2.45 (s, 6H), 1.86 (s, 6H),1.49 (s, 9H) ppm.

The compounds 2 to 15 used in Examples were synthesized by the similarmethod as for the compound 1. The comparative compounds 1 to 5 weresynthesized with reference to well-known literatures in which each ofthe compounds is described.

Example 1 Confirmation of Purity

All of the materials used in the fabrication of the organicelectroluminescent element were subjected to sublimation purification,and it was confirmed that the purity (absorption intensity area ratio at254 nm) was 99.9% or more by using a high performance liquidchromatograph (TSKgel ODS-100Z, manufactured by Tosoh Corporation).

(Fabrication and Evaluation of by Decomposition of OrganicElectroluminescent Element)

A 0.5 mm-thick and 2.5 cm square glass substrate (manufactured byGeomatec Co., Ltd., surface resistance: 10Ω/□) having an ITO filmthereon was put in a cleaning container. After ultrasonic cleaning in2-propanol, the glass substrate was subjected to a UV-ozone treatmentfor 30 minutes. The following organic compound layers were depositedsequentially on this transparent anode (ITO film) by a vacuum depositionmethod.

First layer: HAT-CN: Film thickness 10 nm

Second layer: HT-1: Film thickness 30 nm

Third layer: H-2 and the light emitting material described in Table 1(mass ratio=96:4): Film thickness 30 nm

Fourth layer: ET-1: Film thickness 30 nm

1 nm of lithium fluoride and 100 nm of metallic aluminum were depositedin this order thereon, thereby forming a cathode.

The obtained laminate was put in a glove box purged with a nitrogen gaswithout bringing it into contact with the atmosphere and then sealedwith a sealing can made of glass and an ultraviolet ray-curable adhesive(XNR5516HV, manufactured by Nagase-Chiba Ltd.), thereby obtainingorganic electroluminescent elements 1-1 to 1-10, and comparative organicelectroluminescent elements 1-1 to 1-5, each having a light emittingarea in a 2 mm×2 mm square. For each of the obtained organicelectroluminescent elements, the tests below were carried out. Theresults of the evaluation from the viewpoint of the luminous efficiency,the color purity, and the change in the driving chromaticity are shownin Table 1.

(a) Color Purity

Light was emitted by applying a direct current voltage to each of theelements using a source measure unit 2400 manufactured by TOYOCorporation. The luminance was measured with a luminance meter (BM-8,manufactured by Topcon Corporation). The luminous spectrum and the lightemitting wavelength were measured using a spectrum analyzer (PMA-11,manufactured by Hamamatsu Photonics K. K.). The chromaticity (x, y) wasdetermined from the luminous spectrum when each of the organicelectroluminescent elements was allowed to emit light to a luminance of1000 cd/m² (CIE1931 color system). The y values at that time wereevaluated as the following 3 grades according to the following criteria.

A: Less than 0.12

B: 0.12 or more and less than 0.18

C: 0.18 or more

(b) Change in Driving Chromaticity

Light was continuously emitted by applying a direct current voltage toeach of the organic electroluminescent elements to a luminance of 1000cd/m², and the chromaticity (x′, y′) when the luminance decreased to 500cd/m² was measured from the luminous spectrum (CIE1931 color system).The change in the y values Δy (=|y′−Δy|) before and after thedeterioration by driving was evaluated as 4 grades according to thefollowing criteria.

A: Less than 0.01

B: 0.01 or more and less than 0.02

C: 0.02 or more and less than 0.03

D: 0.03 or more

(c) Increase in Driving Voltage

Light was continuously emitted by applying a direct current voltage toeach of the organic electroluminescent elements to a luminance of 1000cd/m², and the value of an increase in the voltage when the luminancedecreased to 500 cd/m² was evaluated as the following 2 grades.

A: Less than 1.5 V

B: 1.5 V or more and less than 2.5 V

C: 2.5 V or more

TABLE 1 Light Change in Increase in emitting Luminous Color drivingdriving Element No. material color purity chromaticity voltage Element1-1 Compound 1 Blue B A B Element 1-2 Compound 3 Blue B B B Element 1-3Compound 4 Blue B A B Element 1-4 Compound 5 Blue B A B Element 1-5Compound 7 Blue B A B Element 1-6 Compound 8 Blue B B B Element 1-7Compound 9 Blue B B B Element 1-8 Compound 10 Blue B A B Element 1-9Compound 14 Blue B A B Element 1-10 Compound 15 Blue B A B ComparativeComparative Blue C D D element 1-1 compound 1 Comparative ComparativeBlue D D C element 1-2 compound 2 green Comparative Comparative Blue D DC element 1-3 compound 3 green

Example 2

Organic electroluminescent elements were fabricated in the same manneras in Example 1, except that the layer configurations were changed asfollows, and evaluations were carried out in the same manner as inExample 1. The results are shown in Table 2 below. Further, the luminousefficiency in Table 2 below is shown as a relative value, taking theexternal quantum efficiency of the comparative element 2-1 as 1.0.

First layer: HI-2: Film thickness 50 nm

Second layer: HT-2: Film thickness 45 nm

Third layer: H-3 and the light emitting material described in Table 2(mass ratio=96:4): Film thickness 25 nm

Fourth layer: ET-2: Film thickness 5 nm

Fifth layer: ET-3: Film thickness 20 nm

TABLE 2 Light Change in Increase emitting Luminous Color driving indriving Element No. material color purity chromaticity voltage Element2-1 Compound 2 Blue B B B Element 2-2 Compound 5 Blue B A B Element 2-3Compound 6 Blue B B B Element 2-4 Compound 7 Blue B A B Element 2-5Compound 11 Blue B B B Element 2-6 Compound 13 Blue B A B ComparativeComparative Blue C D D Element 2-1 compound 1 Comparative ComparativeBlue D D C element 2-2 compound 2 green Comparative Comparative Blue D DB element 2-3 compound 3 green

Example 3

Organic electroluminescent elements were fabricated in the same manneras in Example 1, except that the layer configurations were changed asfollows, and evaluations were carried out in the same manner as inExample 1. The results are shown in Table 3 below. Further, the luminousefficiency in Table 3 below is shown as a relative value, taking theexternal quantum efficiency of the comparative organicelectroluminescent element 3-1 as 1.0.

First layer: HI-2: Film thickness 10 nm

Second layer: NPD: Film thickness 30 nm

Third layer: The host material and the light emitting material describedin Table 3 (96:4): Film thickness 30 nm

Fourth layer: ET-4: Film thickness 10 nm

Fifth layer: The electron transporting material described in Table 3:Film thickness 20 nm

TABLE 3 Change Electron in Increase Light trans- driving in Hostemitting porting Luminous Color chroma- driving Element No. materialmaterial material color purity ticity voltage Element 3-1 H-3 Compound 1ET-5 Blue B A B Element 3-2 H-3 Compound 3 Alq Blue B A B Element 3-3CBP Compound 7 ET-5 Blue B A B Element 3-4 H-3 Compound 10 ET-5 Blue B AB Element 3-5 CBP Compound 12 ET-5 Blue B B B Element 3-6 CBP Compound14 Alq Blue B A B Element 3-7 H-3 Compound 15 ET-5 Blue B A BComparative CBP Comparative ET-5 Blue C D D element 3-1 compound 1Comparative CBP Comparative ET-5 Blue D D C element 3-2 compound 2 greenComparative H-3 Comparative Alq Blue D D C element 3-3 compound 3 green

Example 4 Preparation of Light Emitting Layer-Forming Coating Liquids

A light emitting material 1 (0.25% by mass) and a host material ADN (5%by mass) were mixed with toluene (94.75% by mass) to obtain a lightemitting layer-forming coating liquid 1.

Light emitting layer-forming coating liquids 2 and 3 were prepared inthe same manner as for the light emitting layer-forming coating liquid1, except that the light emitting material 1 in the light emittinglayer-forming coating liquid 1 was changed to light emitting materials 3and 14.

ITO was deposited on a 25 mm×25 mm×0.7 mm glass substrate to give athickness of 150 nm, thereby forming a film. The film was taken as atransparent supporting substrate. This transparent supporting substratewas etched and washed.

On this ITO glass substrate, 2 parts by mass of PTPDES-2 represented bythe following structural formula (manufactured by Chemipro Kasei Kaisha,Ltd., Tg=205° C.) was dissolved in 98 parts by mass of cyclohexanone forthe Electronics Industry (manufactured by Kanto Chemical Co., Inc.) andspin-coated (2,000 rpm, 20 seconds) to give a thickness of about 40 nm,and then dried at 120° C. for 30 minutes and subjected to an annealingtreatment at 160° C. for 10 minutes to form a hole injecting layer.

PTPDES-2 represents the following structure.

The light emitting layer-forming coating liquids 1 and 3 werespin-coated on the hole injecting layers (1,300 rpm, 30 seconds) to givea thickness of about 40 nm, thereby obtaining light emitting layers.

Subsequently, BAlq represented by the following structural formula wasformed as an electron transporting layer on a light emitting layer togive a thickness of 40 nm by a vacuum deposition method.

Lithium fluoride (LiF) was formed as an electron injecting layer on anelectron transporting layer to give a thickness of 1 nm by a vacuumdeposition method. Metal aluminum was further deposited to 70 nm thereonto give a cathode.

The laminate thus prepared was put into a globe box purged with an argongas, and then sealed with a sealing can made of stainless steel and anultraviolet ray-curable adhesive (XNR5516HV, manufactured byNagase-Chiba, Ltd.) to fabricate organic electroluminescent elements 4-1to 4-3 and comparative elements 4-1 to 4-2.

For the organic electroluminescent elements 4-1 to 4-3 and thecomparative elements 4-1 to 4-2, the same evaluation as in Example 1 wascarried out. The results are shown in Table 4 below.

TABLE 4 Light Change in Increase in emitting Luminous Color drivingdriving Element No. material color purity chromaticity voltage Element4-1 Compound 1 Blue B A B Element 4-2 Compound 3 Blue B B B Element 4-3Compound 14 Blue B B B Comparative Comparative Blue C D D element 4-1compound 1 Comparative Comparative Blue D D D element 4-2 compound 2green

REFERENCE SIGNS LIST

2: SUBSTRATE

3: ANODE

4: HOLE INJECTING LAYER

5: HOLE TRANSPORTING LAYER

6: LIGHT EMITTING LAYER

7: HOLE BLOCKING LAYER

8: ELECTRON TRANSPORTING LAYER

9: CATHODE

10: ORGANIC ELECTROLUMINESCENT ELEMENT

11: ORGANIC LAYER

12: PROTECTIVE LAYER

14: ADHESIVE LAYER

16: SEALING ENCLOSURE

20: LIGHT EMITTING DEVICE

30: LIGHT SCATTERING MEMBER

31: TRANSPARENT SUBSTRATE

30A: LIGHT INCIDENT SURFACE

30B: LIGHT OUTPUTTING SURFACE

32: FINE PARTICLES

40: ILLUMINATION DEVICE

The invention claimed is:
 1. An organic electroluminescent elementcomprising: a substrate; a pair of electrodes including an anode and acathode, disposed on the substrate; and at least one organic layerincluding a light emitting layer, disposed between the electrodes,wherein at least one kind of compound represented by any one of thefollowing General Formulae (I) to (IV) is contained in any layer of theat least one organic layer:

wherein R¹ to R³⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R¹ to R³⁷ are not bonded toeach other to form a ring; X¹ to X³² each independently represents alinking group represented by any one of CR⁶¹R⁶², NR⁶³, O, S, andSiR⁶⁴R⁶⁵; R⁶¹ to R⁶⁵ each independently represent a hydrogen atom or asubstituent; A¹ to A³⁸ each independently represents CR⁶⁶ or N; R⁶⁶represents a hydrogen atom or a substituent, and when two adjacentgroups out of A¹ to A³⁸ are CR⁶⁶, the two R⁶⁶'s may be bonded to eachother to form a ring structure; wherein when X¹ and X² are the same, X¹and X² are not NR⁶³ or S; and wherein when X³¹ and X³² are both NR⁶³, atleast one R⁶³ is not H.
 2. The organic electroluminescent elementaccording to claim 1, wherein at least one kind of compound representedby the General Formula (I) or (II) is contained in any layer of the atleast one organic layer.
 3. The organic electroluminescent elementaccording to claim 1, wherein the molecular weight of the compoundrepresented by any one of the General Formulae (I) to (IV) is 800 orless.
 4. The organic electroluminescent element according to claim 1,wherein the organic layer containing the compound represented by any oneof the General Formulae (I) to (IV) is formed by a vacuum depositionprocess.
 5. The organic electroluminescent element according to claim 1,wherein the light emitting layer is formed by a wet process.
 6. A lightemitting device using the organic electroluminescent element accordingto claim
 1. 7. A display device using the organic electroluminescentelement according to claim
 1. 8. An illumination device using theorganic electroluminescent element according to claim
 1. 9. The organicelectroluminescent element according to claim 1, wherein at least onekind of compound represented by the General Formula (II) is contained inany layer of the at least one organic layer.
 10. The organicelectroluminescent element according to claim 9, wherein the compoundrepresented by the General Formula (II) is a compound represented by thefollowing general formula (V):

wherein R⁴¹ to R⁴⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R⁴¹ to R⁴⁷ are not bonded toeach other to form a ring; R⁴⁸ to R⁵⁵ each independently represents ahydrogen atom or a substituent, and two adjacent groups out of R⁴⁸ toR⁵⁵ may be bonded to each other to form a ring; X⁴¹ and X⁴² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵; R⁶¹ to R⁶⁵ each independentlyrepresents a hydrogen atom or a substituent.
 11. The organicelectroluminescent element according to claim 10, wherein in the GeneralFormula (V), X⁴¹ and X⁴² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, and O.
 12. The organicelectroluminescent element according to claim 10, wherein in the GeneralFormula (V), X⁴¹ and X⁴² are each independently represented by any oneof CR⁶¹R⁶², NR⁶³, and O, and X⁴¹ and X⁴² represent different linkinggroups.
 13. The organic electroluminescent element according to claim10, wherein in the General Formula (V), at least one of R⁴¹ to R⁵⁵ andR⁶¹ to R⁶⁵ is a substituent having any of a fluorine atom, an alkylgroup, a silyl group, and an amino group.
 14. The organicelectroluminescent element according to claim 1, wherein at least onekind of compound represented by the General Formula (I) is contained inany layer of the at least one organic layer.
 15. The organicelectroluminescent element according to claim 14, wherein the compoundrepresented by the General Formula (I) is represented by the followingGeneral Formula (VI)

wherein R⁷¹ to R⁷⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R⁷¹ to R⁷⁷ are not bonded toeach other to form a ring; R⁷⁸ to R⁸⁵ each independently represents ahydrogen atom or a substituent, and two adjacent groups out of R⁷⁸ toR⁸⁵ may be bonded to each other to form a ring; X⁵¹ and X⁵² eachindependently represents a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, O, S, and SiR⁶⁴R⁶⁵; R⁶¹ to R⁶⁵ each independentlyrepresents a hydrogen atom or a substituent; wherein when X⁵¹ and X⁵²are the same, X⁵¹ and X⁵² are not NR⁶³ or S.
 16. The organicelectroluminescent element according to claim 15, wherein in the GeneralFormula (VI), X⁵¹ and X⁵² each independently represent a linking grouprepresented by any one of CR⁶¹R⁶², NR⁶³, and O.
 17. The organicelectroluminescent element according to claim 15, wherein in the GeneralFormula (VI), X⁵¹ and X⁵² are each independently represented by any oneof CR⁶¹R⁶², NR⁶³, and O, and X⁵¹ and X⁵² represent different linkinggroups.
 18. The organic electroluminescent element according to claim15, wherein in the General Formula (VI), at least one of R⁷¹ to R⁸⁵ andR⁶¹ to R⁶⁵ is a substituent having any of a fluorine atom, an alkylgroup, a silyl group, and an amino group.
 19. The organicelectroluminescent element according to claim 1, wherein the compoundrepresented by any one of the General Formulae (I) to (IV) is containedin the light emitting layer.
 20. The organic electroluminescent elementaccording to claim 19, wherein the compound represented by any one ofthe General Formulae (I) to (IV) is a light emitting material containedin the light emitting layer.
 21. The organic electroluminescent elementaccording to claim 20, further comprising a host material in the lightemitting layer.
 22. The organic electroluminescent element according toclaim 21, wherein the host material has a hydrocarbon fused ringstructure having 10 to 50 carbon atoms.
 23. The organicelectroluminescent element according to claim 21, wherein the hostmaterial has an anthracene skeleton.
 24. A material for an organicelectroluminescent element, which is a compound represented by thefollowing General Formula (V′):

wherein R⁴¹ to R⁴⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R⁴¹ to R⁴⁷ are not bonded toeach other to form a ring; R⁴⁸ to R⁵⁵ each independently represents ahydrogen atom or a substituent, and two adjacent groups out of R⁴⁸ toR⁵⁵ may be bonded to each other to form a ring; X⁴¹ and X⁴² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, and O, R⁶¹ to R⁶⁵ each independently represent a hydrogenatom or a substituent.
 25. A material for an organic electroluminescentelement, which is represented by the following General Formula (VI′):

wherein R⁷¹ to R⁷⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R⁷¹ to R⁷⁷ are not bonded toeach other to form a ring; R⁷⁸ to R⁸⁵ each independently represent ahydrogen atom or a substituent, and two adjacent groups out of R⁷⁸ toR⁸⁵ may be bonded to each other to form a ring; X⁵¹ and X⁵² eachindependently represent a linking group represented by any one ofCR⁶¹R⁶², NR⁶³, and O; R⁶¹ to R⁶⁵ each independently represents ahydrogen atom or a substituent; wherein when X⁵¹ and X⁵² are the same,X⁵¹ and X⁵² are not NR⁶³ or S.
 26. A compound for use in an organiclayer of an organic Electroluminescent device represented by anyone ofthe following General Formulae (I) to (IV)

wherein R¹ to R³⁷ each independently represents a hydrogen atom or asubstituent, but two adjacent groups out of R¹ to R³⁷ are not bonded toeach other to form a ring; X¹ to X³² each independently represents alinking group represented by any one of CR⁶¹R⁶², NR⁶³, O, S, andSiR⁶⁴R⁶⁵; R⁶¹ to R⁶⁵ each independently represent a hydrogen atom or asubstituent; A¹ to A³⁸ each independently represents CR⁶⁶ or N; R⁶⁶represents a hydrogen atom or a substituent, and when two adjacentgroups out of A¹ to A³⁸ are CR⁶⁶, the two R⁶⁶'s may be bonded to eachorder to form a ring structure; wherein when X¹ and X² are the same, X¹and X² are not NR⁶³ or S; and wherein when X³¹ and X³² are both NR⁶³, atleast one R⁶³ is not H.